Health and Safety Guidelines for
TYRE FITTERS
The following organisations contributed material which
was used to produce this guideline:
Aim Distributors
Bandag New Zealand Limited
Beaurepaires for Tyres
BMW New Zealand Limited
Bridgestone/Firestone (NZ) Ltd
Continental Vehicle Distributors Limited
Eastwood Forklift Tyres
Environment Canterbury
Environment Southland
Honda New Zealand Limited (LMVD)
Independent Tyre Specialists Limited
Land Transport Safety Authority
Mitsubishi Motors New Zealand Ltd
Motor Trade Association
New Zealand Motor Industry Training Organisation
Oliver Tyre & Rubber Co of New Zealand Limited
Powerpac Tools Ltd
Shell New Zealand Limited
South Pacific Tyres NZ Ltd
Tech Tyre Repairs Ltd
The Tyre General, Temuka
Toyota New Zealand Limited
TRS Agri-Tire Ltd
Tyre Seal New Zealand
U-Save Partsworld
Upper Hutt Tyres and Alignments
Value Tyres Limited
Waihou Engineering
Wellington Motorcycles
Whangarei Truck and Tractor Spares
Young Motors Limited
Published by the Occupational Safety & Health Service
Department of Labour
Wellington
New Zealand
www.osh.dol.govt.nz
Published: October 2001
ISBN 0-477-03650-3
Contents
I: Introduction
5
2: Hazards and How to Avoid Them
Compressed Air ......................................................................................................... 6
Exploding Wheels and Tyres ................................................................................... 8
Heavy Objects ............................................................................................................ 9
Noise .......................................................................................................................... 9
6
3: General Safety Rules
Choice and Care of Hand Tools ............................................................................. 11
Safe Use of Air Tools .............................................................................................. 12
Safe Lifting ............................................................................................................. 13
Protect Your Hearing.............................................................................................. 13
Measuring Noise ......................................................................................................14
Dressing for Safety ................................................................................................. 15
Other Equipment .................................................................................................... 15
New Zealand Standards .......................................................................................... 15
Disposal of Anti-freeze ............................................................................................ 16
10
4: Wheel and Tyre Identification
Passenger Car Tyres ............................................................................................... 18
Light Truck Tyres ................................................................................................... 18
Truck and Bus Tyres .............................................................................................. 19
Tractor Tyres .......................................................................................................... 20
Industrial Tyres ...................................................................................................... 21
ATV Tyres ............................................................................................................... 21
17
5: Points to be Aware of When Fitting Tyres
Space Saver Tyres .................................................................................................. 23
Intermixing — General ............................................................................................ 23
Intermixing — Passenger Cars ............................................................................... 24
Intermixing — Light and Heavy Commercial Vehicles.......................................... 24
Dual Tyres ............................................................................................................... 24
Forkhoist and Industrial Vehicles .......................................................................... 25
Forklift Industrial Tyres And Rims ....................................................................... 25
23
6: Demounting Tyres
Removal of Common Assemblies ........................................................................... 29
Light Truck, Truck Tyres — Multi-Piece Rims ...................................................... 30
Demounting Off the Vehicle ................................................................................... 30
Demounting On The Vehicle .................................................................................. 32
29
7: Repairing Tyres
Zipper Hazard ......................................................................................................... 35
Identifying the Hazard ........................................................................................... 35
Inspection ................................................................................................................ 36
Deflating a Zipper ................................................................................................... 36
Roadside or Off-Site Servicing ............................................................................... 37
Safety Rules for Road Side Servicing .................................................................... 38
Tyre Sealants .......................................................................................................... 38
34
8: Tyre Mounting Safety Precautions
To Determine Compatible Rim Width for Tyre Sizes .......................................... 40
40
Mounting
Mounting
Mounting
Mounting
Tyres ....................................................................................................... 41
of Common Assemblies Tyres ............................................................... 42
off the Vehicle ........................................................................................ 44
on the Vehicle — Agricultural ............................................................... 45
9: Rim and Wheel Types
Drop Centre or Well Base Rim ...............................................................................47
Flat Base Rims .........................................................................................................47
Wide Base One-Piece Rim ...................................................................................... 48
Multi-Piece Rims ..................................................................................................... 48
Semi-Drop Centre Rim ........................................................................................... 49
Divided Wheels ....................................................................................................... 49
47
10: Off-the-Vehicle Wheel Balancing
50
11: On-the-Vehicle Wheel Balancing
51
12: Balancing Truck Assemblies
53
13: Roadside Tyre Repairs
54
14: Tyre Inflation Pressures
Free Air Dispensers ................................................................................................ 56
56
15: Use of Jacks
57
16: Tyre Safety Cages
58
17: Identifying Vehicles Fitted with Airbags
Ways of Identifying Vehicles Fitted with Air Bags ............................................... 59
Personal Safety ....................................................................................................... 61
The Costs of Accidentally Deploying an Air Bag .................................................. 61
59
18: The Employer’s Responsibilities
Public Access to Tyre Change Areas ..................................................................... 63
Working on Sites as a Contractor ......................................................................... 63
62
19: The Employee’s Responsibilities
64
20: Employee Training Schedule
65
21: Where to Get Advice
Land Transport Rule: Tyres and Wheels .............................................................. 66
Tyre Safety Issue Boundary Between OSH and LTSA ......................................... 66
Web Sites (NZ) ........................................................................................................ 66
References ............................................................................................................... 67
Other Tyre-Related Web Sites................................................................................ 68
66
Appendix 1: Wheel Restraint Device
69
Appendix 2: Tyre Construction
Crossply (or Bias Py) Construction. ...................................................................... 70
Textile Radial Construction .................................................................................... 70
Steel-Belted Radial Construction ........................................................................... 70
70
Appendix 3: Glossary of Terms
71
Health and Safety Guidelines for Tyre Fitters 4
I: Introduction
T
he Occupational Safety and Health Service has produced this guideline as
part of its continuing drive to reduce the incidence and severity of
workplace accidents. It is a guide to safe work methods and practices
wherever motor vehicle or industrial tyres are inflated by compressed air.
Accidents while inflating tyres tend to be serious, because of the high air
pressures and the heavy objects involved. All too often apprentices or
inexperienced workers are asked to work with tyres without adequate
training or even knowing the risks involved.
Employers must ensure that every tyre fitter is adequately trained, and
knows, understands, and uses the correct procedures and equipment.
Employers are also responsible for ensuring that contractors including tyre
fitters operate safely while on their premises. This guide will help employers understand their duties and responsibilities.
Tyre fitters must be
adequately trained,
and use the correct
procedures and
equipment.
Tyre fitters must use the correct procedures and equipment, and work in a
way which ensures the safety of themselves, and others.
This guide draws on an earlier Department of Labour booklet Tyre Safety,
which since 1988 has been a standard reference for the tyre industry. It
has been updated to take account of changes in technology and new safety
issues such as anticipating zippers in the sudden failure of steel-reinforced
sidewalls, and safety rules for wheel alignments on vehicles fitted with air
bags. Other health and safety issues include the use of antifreeze in tyres,
choice of tyres and combinations of tyres. There is additional information
on managing hazards of lifting, and hazards of noise. We have attempted to
define the boundary between Occupational Safety and Health (OSH) and
the Land Transport Safety Authority (LTSA), both regulators with interests
in tyre safety.
This guide has been written with the help of several members of the tyre
industry, and people with a professional interest in safe work with tyres. It
is a consensus of what these people consider is safe practice. It does not
have the force of law, but may be presented to a Court as a statement of
practicable steps in terms of the Health and Safety in Employment Act
1992. In this guide, “shall” indicates that a statement is mandatory.
“Should” indicates a recommendation.
Health and Safety Guidelines for Tyre Fitters addresses new safety and
health issues, building on the proven support for Tyre Safety.
Health and Safety Guidelines for Tyre Fitters 5
2: Hazards and How
to Avoid Them
If you work with tyres, there are four major sources of hazard. They are:
• compressed air;
• heavy objects;
• exploding wheels and tyres;
• noise.
Compressed Air
Your eyes are particularly at risk, both from high-velocity air and from
particles of dust, metal, oil, and other debris, which may be propelled by the
air. Always wear suitable eye protection. The rest of your body is also at risk
from compressed air. Suitable overalls will protect the skin from light
particles of debris, provided they are not blown at a high velocity. However,
no overalls can protect you against high-velocity air at close range. Particles
may be blown right through your overalls and skin and into your body. The
air can be blown straight into your bloodstream, causing swelling and intense pain, particularly if you have any cuts, punctures or sores which make
entry easier. The air may be carried to the small blood vessels of the brain
and cause them to burst, resulting in death.
ACCIDENT CASE
Brushing down with compressed air
A worker received a small puncture in the palm of his hand from a
metal spike. Soon after he used a compressed air gun to blow dirt and
blood from his hand. The air enlarged the puncture and blew up his
hand like a small balloon. He suffered severe pain and needed hospital treatment.
All pressure gauges and control devices must be checked against a master
pressure gauge at least annually or straight after any heavy impact. Your life
may depend on it.
Compressed air hand tools (but not compressors and associated equipment)
are exempt from the Health and Safety in Employment (Pressure Equipment, Cranes, and Passenger Ropeways) Regulations 1999 (PECPR Regula-
Health and Safety Guidelines for Tyre Fitters 6
tions). Good practice would dictate sound maintenance of such tools and
monitoring their condition on an ongoing basis.
Compressors must meet
the requirements in the
appropriate code of
practice.
Compressors and associated equipment are covered by the draft Code of
Practice for the Design, Operation, Maintenance and Servicing of Pressure
Equipment. The code will exempt compressors from inspection by an inspection body, but controllers should consult it for other requirements. Receivers
may require inspection, and the current requirements can be ascertained
from Table 4.1 of AS/NZS 3788:1996 Pressure equipment - In-service inspection. Note that any exemption from inspection of an item does not relieve
controllers of their other responsibilities under the PECPR Regulations or
the Health and Safety in Employment Act 1992 or other regulations made
under the Act.
Belt transmissions on compressors shall be guarded — even compressors on
truck decks.
Remember that air under pressure expands with an increase in temperature.
Never apply heat from a welding torch or any other source to a rim or tyre
which is under pressure. This has caused fatal explosions.
KEY POINTS
Where possible,
always deflate all
tyres before removing
them from vehicles.
1
2
Where possible, always deflate all tyres before removing them
from vehicles.
3
Never point an air hose at yourself or anyone else.
4
5
Never use damaged air hoses or fittings.
6
7
8
9
10
Don’t leave air hoses where vehicles or any other heavy equipment
can run over them, because this can weaken or damage them.
Always remember to store equipment such as air lines properly.
Don’t leave them lying around where they can cause accidents or
get damaged.
Don’t kink the air hose to stop or cut down the airflow — you
weaken the hose. Use the pressure control for adjusting air pressure.
Never leave unattended air lines attached to tyre assemblies.
Never use an air line that is not fitted with a pressure gauge or a
pressure control device.
Check the accuracy of pressure gauges regularly.
Never heat a rim with an inflated tyre on it.
Health and Safety Guidelines for Tyre Fitters 7
11
12
Compressed air should only be used to inflate tyres or operate
tools.
Compressed air should never be used for cleaning. A vacuum
cleaner should be used to clean work areas.
Exploding Wheels and Tyres
Large tyres and wheel assemblies are heavy objects, but when they explode
they are thrown violently by the force of the escaping compressed air. An
exploding wheel is a high-speed projectile which can kill or seriously maim
anyone in its path.
ACCIDENT CASE
Broken hand when motorcycle tyre over-inflated
The bead of a new tyre would not seat as the fitter was fitting the tyre
to the rear wheel of a motorcycle. He raised the inflation pressure to try
to force the bead to the corner of the rim; tyre pressure soon reached
420 kPa (60 psi), which was 150% of the maximum pressure. At this
pressure, or slightly more, the tyre bead blew, forcing his hand against
the chain and sprocket with enough force to break bones in his hand.
Divided wheels, split rims and locking rings are especially likely to explode
because of poor maintenance, incorrect fitting, and assembly or disassembly
while inflated. The most common faults are over-inflation, removal of split
rim fastening nuts instead of wheel fastening nuts, failure to ensure correct
seating of split rims or tyre beads, and the use of damaged parts, or parts
with lesser strength than original. Be aware that non-original after market
nuts and bolts may be inadequate. It is essential to deflate tyres before
wheel removal to ensure that removing the wrong nuts does not cause
serious or fatal accidents.
ACCIDENT CASE
Wheelbarrow tyre caused injury
A car tyre or even a wheelbarrow tyre is a potential killer. A tube burst
while a wheelbarrow tyre was being inflated and the rim flew up,
striking the worker on the head and injuring him.
Zippers expel shrapnel
of rubber and steel
which can cause
serious injuries.
Zippers which tear tyre sidewalls expel shrapnel of rubber and steel which
can penetrate skin and eyes. Escaping air can easily blow tyres across a
workshop with force.
Health and Safety Guidelines for Tyre Fitters 8
KEY POINT
Because of the risk of explosion, you must use tyre safety cages, or other
suitable restraining devices, at all times.
Heavy Objects
Tyre and wheel assemblies of large vehicles are often too heavy to be handled safely by one person. Even the strongest person can suffer a hernia,
slipped disc, sprain or broken bone when handling loads that are too heavy.
Such injuries can be very painful and limiting.
Tyres may be too
heavy to be lifted by
safely hand: get help
or use a mechanical
aid.
KEY POINT
Get help with big loads.
Noise
Given many years of tyre fitting, hearing damage may affect tyre fitters.
Causes are compressed air blowing freely, and noise from impact wrenches,
and from wheel parts and tools dropping on concrete floors. The impact of
steel on concrete floors can be quietened with rubber mats.
KEY POINT
Always wear ear plugs or muffs, because the noise can affect your hearing
long-term.
Health and Safety Guidelines for Tyre Fitters 9
3: General Safety
Rules
Here are the general safety rules you should observe at all times:
1
2
3
Where possible, deflate all tyres especially on divided rims and
multi-piece rims before removing them from vehicles.
4
Don’t start any job with damaged or unsatisfactory equipment. If
any of the gear to be used, such as air hoses, gauges, mallets, tyre
levers, box spanners, or safety glasses, is not in good working
condition, STOP! Tell your supervisor of the problem immediately,
and have it put right.
5
When starting any repair, ensure you are familiar with the type of
vehicle, and the procedures required, before you begin work.
Don’t wear loose fitting clothing as it can get caught in some
machines.
Don’t start any job for which you have not been trained, unless you
are being directly supervised by a person who is both competent
and authorised to train you.
Is it a farm vehicle, truck, bus, car or industrial tyre. Is it tubeless
or tube-type? Is the rim of a drop centre, semi-drop centre, divided,
two-piece, three-piece type? By this stage you should know whether
or not you have the necessary experience to do the job safely. If
not, STOP! Tell your supervisor that you are not familiar with the
particular tyre. Your supervisor should either refer you to the
correct manuals or wall charts, or provide someone to instruct you.
Make sure you are
familiar with the type of
vehicle, and the
procedures required,
before you begin work.
6
Correct manuals or wall charts should always be available. Refer to
them whenever you have any doubts. If still in doubt, tell your
supervisor.
7
Never skylark or play practical jokes in a work area. It is dangerous
and will make you liable should you injure anyone.
ACCIDENT CASE
Skylarking with Compressed Air
Two employees were using a compressed air hose to blow dust from
their clothing. One man pushed a hose between the legs of a fellow
worker from behind. The victim’s lower bowel was torn open, his abdomen ballooned with air and he died from his injuries.
NOTE: This incident occurred in a carpenter’s workshop, but the message is relevant to the tyre industry.
Health and Safety Guidelines for Tyre Fitters 10
Use a cage guard
when intially inflating
tyres, and stand well
aside.
8
Keep all electrical leads and air lines clear of walkways at all times.
They should be coiled and stored away when not in use. They
should be inspected each time before use and not used if there is
any sign of damage.
9
Always use a cage guard or other suitable restraining device when
one is available, even for small tyres such as wheelbarrow tyres.
Although not as dangerous as large tyres and multi-piece units,
they have still been known to cause serious injuries. Large tyres,
such as truck, bus, grader, tractor tyres, etc., and multi-piece units,
must always be isolated in a suitable device during inflation.
ACCIDENT CASE
Inexperienced tyre fitter thrown by exploding tyre
An 18-year-old tyre fitter sat on the tailgate of the service truck while
he waited for the truck tyre on the ground beneath him to inflate. He
had only 9 months’ experience, and had not previously seen the type
of rim, a trilex type rim, to which he had fitted the tyre. There was no
direct supervision of his service work, and he had used his boot instead
of a soft headed hammer to try to seat the rim pieces. Placing the tyre
beneath the tailgate was ineffective, because the tailgate was hinged
and able to swivel upwards when the tyre exploded. When the tyre/rim
assembly exploded, he was catapulted 1.8 metres into the air.
10
When initially inflating tyres, stand well aside.
(a) For car and motorcycle tyres, use a clip-on chuck and hand
control device.
(b) For light truck, truck and industrial tyres, use a clip-on chuck
and 2-metre hose connected to a hand control device.
11
Waste bins for rubber or other flammable refuse should have closefitting lids, and should not be used as ashtrays.
KEY POINTS
Make sure that you are safely dressed, use the right equipment and have the
right information.
Choice and Care of Hand Tools
1
2
Tyre levers must be kept free of jagged edges and rust.
Hammers are used for both mounting and demounting tyres. A
rubber end can be used for driving on both tyres and rims. Always
wear safety goggles when using striking or struck tools. Never use
Health and Safety Guidelines for Tyre Fitters 11
a hammer to strike another hammer. Never use a striking tool with
loose or damaged handle. Discard any striking or struck tool if it
shows dents, cracks, chips, or mushrooming.
Safe Use of Air Tools
Air tools are mostly used for loosening and tightening wheel nuts. Safety is
essential when using the air tool. If you are not sure, ask your supervisor.
Always use correct
torque for the type of
wheel.
1
Always wear protective equipment and clothing such as eye wear or
a face shield, overalls, gloves and other necessary protective clothing. Use protective barriers where necessary.
2
When mounting and dismounting accessories such as impact
sockets and buzz out wheels, make sure to disconnect the tool from
the air line or to shut off the air line.
3
4
Always use the correct accessories. Do not use worn, warped and
damaged accessories.
5
Check the air hose and connections before use. (If the hose comes
away while you’re working with the inflator or the air tool, it can
damage the vehicle, or injure you.)
6
7
Keep the air hose clear of working parts of the air tool so that it
doesn’t get caught in them.
8
9
Do not use the air hose for supporting, lifting or lowering the tool.
10
Do not use the tool in a place which is filled with flammable gas.
Friction or bumping of the tools with the work or another object
may cause sparks and there is a possibility that a fire or an explosion may take place.
11
Never use or continue to operate the tool when you feel abnormal
vibration, hear unusual sounds, notice unusual changes in speed or
find any other irregularities.
12
Torque for a particular wheel shall be followed. All nuts should be
manually checked for torque with a manual wrench.
Always use the correct air hose and fittings such as an inlet bushing, hose nipple and hose coupler and inspect them regularly for
wear and damage and replace when necessary.
Check that all attachments are tight before starting the air tool.
Remember to always disconnect the tool from the air supply when
changing attachments.
Make sure before use that the tool runs as per its specifications.
The tool should be used according to its capacity and only for its
own purpose. Do not burst into full speed operation. Avoid any
bumping action and excessive pressure.
Health and Safety Guidelines for Tyre Fitters 12
Safe Lifting
To avoid painful back strains or more serious injury, use a trolley or lifting
equipment where possible or get help.
Even when lifting or picking up light objects, injury can occur if correct
lifting technique is not followed.
When rolling or bowling wheels, always keep them under control. Don’t roll
or bowl them in an uncontrolled manner across the workshop floor, endangering fellow workers.
KEY POINTS
When you are lifting manually:
Always keep wheels
under control when
rolling or bowling
them.
Always get help with
heavy loads.
1
2
3
Size up the load. If too heavy or awkward get help. (Extra people
for a team lift or use a lifting device.)
4
Get a safe grip using the palms of your hands. When you have a
firm grip on the object with both hands, lift by straightening your
legs.
5
6
7
Don’t jerk or twist your body when lifting or carrying.
Position your feet for good balance as close as possible to the object
to be lifted. Crouch as close to the load as possible.
At all times keep your back straight. The bend comes from your
hips and knees. Bend at the knees and keep your back fairly
straight, not arched.
Always get help with heavy and/or awkward tyres.
REMEMBER: Your back is most at risk when it is bent or twisted.
Protect Your Hearing
Sound is such a common part of life that we take it for granted It permits
us enjoyable experiences such as listening to music. It permits us to communicate; it alerts or warns us — a knock on the door, a siren or alarm, the
chattering valves of a car, a squeaking wheel.
Unfortunately long-term exposure to loud sounds can damage our hearing.
Warning signs should
be displayed in noise
hazard areas.
People suffering from occupational deafness experience a distortion of the
sounds they hear. People can no longer distinguish between some words, or
indeed, hear what is being said. Hearing aids offer very limited benefit for
some people with noise-induced hearing loss.
Health and Safety Guidelines for Tyre Fitters 13
Some individuals are more sensitive to noise than others and will lose
hearing more readily through noise exposure.
Management of the hazards of noise, and a technical description of noiseinduced hearing loss, can be found in the Approved Code of Practice for
Management of Noise in the Workplace.
Measuring Noise
Sound is measured in decibels or dBA.
If you are exposed continuously to sounds of 85 dBA over an 8-hour day,
this can lead to hearing damage if hearing protection is not worn. Repeated
long-term daily exposure for 1 or 2 hours per day to sounds of more than 90
dBA can lead to hearing damage if protection is not worn.
If you are using an impact gun to loosen wheel nuts, or are standing next to
a noisy compressor, the noise level can be well over 90 dBA. Hitting metal
objects with a hammer, or dropping steel tyre levers on to concrete floors,
can produce very loud sounds that may lead to hearing damage.
Compressed air blown from a hose can be loud, especially when it strikes a
solid edge.
As the noise level gets higher, damage will occur over a shorter period.
ARE YOU AT RISK?
Noise from an impact
gun can damage your
hearing: always use
hearing protectors.
Fill out this simple quiz to see if your hearing is at risk.
1. At work, do you have to shout to make yourself understood by somebody about an arm’s length away?
YES
NO
2. Do you get ringing or buzzing in your ears after work, or after particular
jobs at work?
YES
NO
3. Does your family say you have difficulty hearing them when you get
home?
YES
NO
4. Do you have to turn up the volume on the TV or radio after a day at
work?
YES
NO
5. Do you often have to ask people to repeat things they’ve just said?
YES
NO
If you have answered “YES” to any of these questions, chances are that
noise in your workplace could be putting your hearing at risk.
Health and Safety Guidelines for Tyre Fitters 14
KEY POINT
Compressed air for blowing should come from low-pressure air lines, using
special nozzles. Hearing protection must be worn while using impact tools.
Dressing for Safety
One way to help prevent injury at work is to dress safely. Employers have a
duty to provide suitable protective clothing and equipment. Workers have a
duty to wear and use it.
The minimum requirements when working with or fitting tyres are:
A typical lace-up
safety shoe with
protective toe cap.
A leather glove with
gel-filled palm to
protect against
vibration. Designed
for use with medium
to high-impact tools.
1
Industrial overalls, which should be close fitting (particularly
around the wrists) and worn fastened to the neck. Sleeves should
be kept down, not rolled up.
2
Eye protection is essential. Your eyesight is precious; an accident
could blind you for life. Various types of goggles or visors are
satisfactory, but if spectacles are used, they must be fitted with
side shields.
3
Safety footwear with protective toecaps, which is necessary when
handling heavy items such as truck, grader, bus, or other large
vehicle wheels and tyres. Even where only light car wheels and
tyres are handled, footwear must be adequate. Wearing thongs,
sandals, sandshoes or other similar footwear is unsafe and may
cause unnecessary injuries.
4
5
6
Hearing protection must be worn when working with or near
impact guns or noisy equipment, including some compressors.
7
High-visibility clothing (fluorescent vests) must be worn by fleet
service persons when working on the roadside.
Knee pads will protect your knees from injury when kneeling on
hard or rough surfaces.
Gloves help protect your hands from injury. Wear gloves when
handling sharp tools or checking for punctures. Sharp objects
protruding from tyres can cut hands.
Example of hivisibility vest,
suitable for day or
night conditions.
Other Equipment
Other equipment may be necessary in particular circumstances. Only the
correct hammers, levers, lubricants, bolts, and other tools are to be used.
Never use equipment that you know or suspect is faulty or inadequate.
Report the fault or inadequacy to your supervisor.
Health and Safety Guidelines for Tyre Fitters 15
New Zealand Standards
No protective clothing or equipment is suitable unless it provides adequate
protection from the particular hazards likely to be met. The New Zealand
Standards Association has produced a range of standards and specifications
for protective clothing and equipment. The Occupational Safety and Health
Service (OSH) recommends that all clothing and equipment comply with the
relevant standard where one exists. There are New Zealand Standards for
eye protection, overalls, safety footwear, industrial gloves, and many other
types of equipment. All products accepted as complying with the New Zealand Standard, or a suitable overseas standard accepted for use in New
Zealand, will bear a Standard Certification Mark. Further information may
be obtained from the Standards Association of New Zealand.
Disposal of Antifreeze
Antifreeze is likely to be present in water-filled tractor tyres used in cold
climates. Ethylene glycol is a highly toxic chemical used for antifreeze.
Antifreeze solution could create handling and disposal problems. When
draining antifreeze solution, keep in mind that cats and dogs are attracted
by the ethylene glycol, and are likely to drink any that is left in an uncovered container or in puddles on the ground. Even small quantities swallowed
will be fatal.
Draining should occur on an area of sealed ground as antifreeze drained on
to broken ground is likely to contaminate the property or groundwater.
Spills should be contained with absorbent material and the advice of the
territorial local authority sought to arrange disposal.
Antifreeze is often
added to the water in
water-filled tractor
tyres in cold climates.
Always drain the antifreeze into a clean and uncontaminated sealable container. The container should be labelled and dated for future identification,
and stored in a clean, dry and secure place where spills can be contained.
Antifreeze should be reused unless it is contaminated or several years old.
Ethylene glycol will also be present in a number of tyre sealants.
Disposal of antifreeze in the sewage system or in septic tanks may only
occur if it is authorised, and requires consent from your Territorial Local
Authority. Antifreeze for disposal in sewers must be diluted to 20% to 30%;
15% or less for disposal in septic tanks. Antifreeze must not be disposed of
in storm water or allowed to enter streams. Ask your local authority or
regional council about correct disposal.
Some tractors used in cold climates have methylated spirits as an antifreeze
in the tyres. Methylated spirits (or other hydrocarbons) should be placed in
sealed containers, but should not be used in tyres. In small quantities,
volatile hydrocarbons may be disposed of by evaporation, by placing them in
an open nonporous container in a secure well-ventilated area.
Some farmers add calcium chloride to tyre ballast water. Water containing
calcium chloride is more dense than pure water. Calcium chloride lowers the
freezing point and acts as anti-freeze. For advice on disposal, ask your
Territorial Local Authority.
Health and Safety Guidelines for Tyre Fitters 16
4: Wheel and Tyre
Identification
A
lways be sure that a tyre is mounted on to the correct size and type of
rim. It is dangerous to install a tyre of one rim diameter on a rim of a
different diameter. Also, you should never mount or use damaged tyres,
tubes or rims. Always replace a tyre on a rim with another tyre of exactly
the same rim diameter designation and suffix letters. For example a 16-inch
tyre goes with a 16-inch rim. You should never mount a 16-inch diameter
tyre on a 16.5-inch rim. It may be possible to pass the tyre over the lip or
flange of the rim but the tyre cannot be inflated enough to position itself
against the rim flange. If you attempt to seat the tyre bead by inflation, it
will break with explosive force and could cause serious injury or death.
Markings show rim
width and diameter in
inches.
ACCIDENT CASE
Exemplary damages: mismatching tyre and rim
During the fitting of a new 15-inch tyre in the defendant’s tyre bay, the
plaintiff was severely injured when the tyre exploded on the 15.3 inch
wheel rim as the tyre was being inflated. The plaintiff’s injuries were
severe — he suffered severe shock; intra-abdominal bleeding and
injury to his liver; lacerations to his scalp; puncture wound over the left
shoulder; a closed displaced fracture of the left arm; compound
fracturing of the shafts of the second, third and fourth fingers of his left
hand; crushed and fractured ribs; left leg almost severed through the
knee, and some unspecified brain damage.
The plaintiff was awarded exemplary damages.
KEY POINT
Rims of different diameters and tapers cannot be interchanged. Diagrams
below illustrate the difference between rims of two different tapers and
diameters.
Diagrams show the
difference between correct
and incorrect seating for
different combinations of
tyres and rims.
Health and Safety Guidelines for Tyre Fitters 17
Passenger Car Tyres
In general, tyres have two basic size markings. These indicate the section
width of the tyre (when fitted to its design rim) and the rim diameter on
which it fits. Crossply car tyres are normally designated in inches, for
example a 6.50 - 13 is a tyre nominally 6.50-inch wide fitting a 13-inch rim.
Radial car tyres are normally designated in millimetres and inches with the
letter “R”: for example, a 175R13 is a radial tyre nominally 175 mm wide
fitting a 13-inch rim. This marking alone, however, does not indicate the
shape which a tyre takes up on the rim, and it is this factor which has
changed considerably in recent years. Tyres have become smaller in diameter but at the same time much wider in section, i.e. more “squat”. Great
care should be taken when selecting tyres to ensure that the correct size
and type are being fitted.
Crossply
6.50 - 13 6PR
Ply rating
Nominal rim diameter (inches)
Nominal section width (inches)
Radial
185 S R 14
Nominal rim diameter (inches)
Radial
Speed rating symbol
Nominal section width (mm)
P 185/60 R 14 82 H
Speed rating symbol
Load index
Nominal rim diameter (inches)
Radial
Nominal aspect ratio (%)
Nominal section width (mm)
Passenger tyre
220/65 R 390 97 V
Speed rating symbol
Load index
Nominal rim diameter (mm)
Radial
Nominal aspect ratio (%)
Nominal section width (mm)
Light Truck Tyres
7.50 - 16 10PR
Ply rating
Nominal rim diameter (inches)
Nominal section width (inches)
Health and Safety Guidelines for Tyre Fitters 18
31 x 10.50 R 15
Nominal rim diameter (inches)
Radial
Approximate section width (inches)
Approximate overall diameter (inches)
195 R 14 LT or C
Light truck or commercial
Nominal rim diameter (inches)
Radial
Nominal selection width (mm)
LT 235/85 R 16 115/113 L
Speed rating symbol
Load index - single/dual
Nomination rim diameter (inches)
Radial
Nominal aspect ratio (%)
Nominal section width (mm)
Light truck tyre
Truck and Bus Tyres
These are normally marked in a similar manner to car tyres, for example:
•
10.00 - 20 is a crossply tyre but a 10.00R20 is a radial ply tyre.
Both have a nominal section marking of 10 inch and fit a 20-inch
rim.
•
11 - 22.5 is a crossply tyre but a 11R22.5 is a radial ply tyre. Both
have a nominal section marking of 11 inch and fit a 221/2 --inch rim.
The ‘22.5' tyres are of tubeless construction and have a tubed tyre
counterpart. For example 9.00R20 and a 10R22.5 have similar
outside dimensions and the same load capacity, but the first is a
tubed type and the second tubeless.
•
Check the tyre for these markings on the sidewall.
Crossply - or x between markings
Radial tubed or tubeless
10.00 R 20 16PR
Ply rating
Nominal rim diameter (inches)
Radial construction
Nominal section width (inches)
Health and Safety Guidelines for Tyre Fitters 19
11 R 22.5 16PR
Ply rating
Nominal rim diameter (inches)
Radial construction
Nominal section width (inches)
295/80 R 22.5 149/146 L
Speed Rating
Load index - single/dual
Nominal rim diameter (inches)
Radial construction
Nominal aspect ratio (%)
Nominal section width (mm)
Tractor Tyres
These come in two types of markings or a combination of both, the difference being a change in nominal section width when tyres started to be
fitted to wider rims. For example:
• 14 - 30 where 14 Section marking 30-inch diameter, or
• 16.9 - 30 where 16.9 Section width on wide-base rim 30-inch diameter, or
• 16.9/14 - 30 Dual size marking
18.4 - 30 8PR
Ply rating
Nominal rim diameter (inches)
Nominal section width (inches)
18.4 R 30 142 A8
Speed rating symbol
Load index
Nominal rim diameter (inches)
Radial
Nominal section width (inches)
Health and Safety Guidelines for Tyre Fitters 20
520/70 R 30 151 D
Speed rating symbol
Load index
Nominal rim diameter (inches)
Radial
Nominal aspect ratio (%)
Nominal section width (mm)
Industrial Tyres
21 x 8 - 10 14PR
Ply rating
Nominal rim diameter (inches)
Nominal section width (inches)
Nominal overall diameter (inches)
405 x 130 - 305
Nominal rim diameter (mm)
Nominal section width (mm)
Nominal overall diameter (mm)
10.00 - 20 16PR IND
Industrial construction
Ply rating
Nominal rim diameter (inches)
Nominal section width (inches)
ATV Tyres
AT 22 x 8 - 10
Nominal rim diameter (inches)
Nominal section width (inches)
Nominal overall diameter (inches)
All terrain
Health and Safety Guidelines for Tyre Fitters 21
TYRE RATINGS
RATING / SPEED
J
100 KPH
Q
160 KPH
K
110 KPH
R
170 KPH
L
120 KPH
S
180 KPH
M
130 KPH
T
190 KPH
N
140 KPH
U
200 KPH
P
150 KPH
H
210 KPH
For higher speeds:
V
240 kph
•W
270 kph
•Y
300 kph
• For tyres having a maximum speed capability of more than 240 kph,
a ZR may appear in the size designation. For tyres having a maximum
speed capability greater than 300 kph, a ZR must appear in the size
designation.
Health and Safety Guidelines for Tyre Fitters 22
5: Points to be Aware
of When Fitting Tyres
KEY POINT
These recommendations apply regardless of whether the vehicle is front- or
rear-wheel drive, front or rear-engined.
Space Saver Tyres
Space saver is the term commonly used to describe temporary-use spare
tyres. Their smaller size reduces storage space requirements and weight,
hence the name. Unlike a standard spare tyre their use is for emergency
purposes only, and strictly in accordance with the safety instructions
attached to the wheel. The most common wheels are normally in bright or
contrasting colours, with tyres about the width of a motorcycle tyre.
Space saver tyres
should only be used in
an emergency.
Space saver tyres should only be used in an emergency to get the driver
directly home or to a place to get the regular tyre repaired and refitted to
the vehicle. Space saver tyre users should also be careful to comply with the
tyre’s inflation requirements (commonly about 350 - 420 kPa (50 - 60 psi),
i.e. much higher than a normal car tyre) and speed restriction (maximum 80
kph). If drivers follow these guidelines, and their space saver tyre is in good
condition, it’s safe to drive on.
However, you need to remember that the vehicle’s handling may be affected
when a space saver tyre is fitted. Never fit more than one space saver tyre
to a vehicle.
Intermixing - General
All steering wheel movements produce lateral force on the tyres. The reaction of a tyre to these lateral forces varies according to its structure. Therefore, for interchangeability of tyres without modification of the vehicle
handling characteristics, it is necessary to take into account the tyre size
and construction. Ideally, tyres should be in complete sets of the same type
and construction. Some intermixing is allowable, however, while other
combinations are either not recommended or not permitted. Basic rules:
1
2
Tyres and rims must always be matched.
Tyre tread patterns fitted to the same vehicle axle should be
matched. Tyres on the same axle shall be of the same nominal size
and be of similar construction.
Health and Safety Guidelines for Tyre Fitters 23
3
Unidirectional tyres must be correctly fitted so that when the wheel
is fitted to the vehicle, the direction of rotation as indicated by the
arrow moulded into the tyre side wall is forward.
4
Asymmetric tread tyres must be fitted the right way round on the
rim so that the respective side walls are in contact with the correct
side of the rim. These must be fitted so that the “outside” sidewall
marking is facing outward.
5
It is recommended that all the tyres fitted to a light vehicle be
either bias-ply or radial ply construction and not a mix of both.
Should this become a mandatory requirement in the proposed Land
Transport Rule: Tyres and Wheels, 5.1 and 5.2 will be omitted.
Unidirectional tyres
must be fitted so that
they rotate in the
direction of the arrow.
5.1 If crossply and radial tyres are mixed, the radials must be
fitted to the rear axle.
5.2 If textile radial and steel radial tyres are mixed, the steel
radial should be fitted to the rear axle.
6
If radial tyres of different aspect ratio are mixed, the tyres of
lowest aspect ratio must be fitted to the rear axle.
Intermixing - Passenger Cars
In addition to the conditions above, this condition applies:
1
2
If a space saver has been fitted for emergency use, the space saver
must be returned to the spare wheel position as soon as possible.
Only one space saver shall be fitted to a car at a time.
Intermixing - Light and Heavy Commercial Vehicles
In addition to the conditions above, these conditions apply:
1
Tyre tread patterns fitted to the same vehicle axle should be
matched. Tyres on the same axle shall be of the same nominal size
and be of similar construction.
2
Radial tyres may only be fitted to the front of a vehicle with
crossply rear tyres if the rears are duals.
NOTE: Care should be taken to ensure that any interchanging of
wheels does not result in incorrect fitments.
Dual Tyres
Tyres paired as duals require special treatment to ensure maximum potential mileage, regular wear and safety to both operator and tyre service
persons.
Health and Safety Guidelines for Tyre Fitters 24
• Correct Spacers and Wheel Offsets
Ensure that correct spacer bands or correct offset wheels are used that
provide adequate clearance between tyres and minimise trapping of stones
and other objects. Be careful not to over-tighten artillery-style wheels as
spacers can become deformed and buckled.
• Mixing of Patterns or Constructions
For maximum safety
and efficiency, dual
wheels require special
treatment.
Mismatching of tyres can have a profound effect on tyre life. Radial and
crossply constructions should not be dualled together, nor should rib and lug
tyres, as irregular wear will develop and tyre life will be adversely effected.
• Permissible Diameter Differences
It is important that dualled tyres are of the same size (diameter) otherwise
the larger tyre will be overloaded and the smaller tyre, lacking proper road
contact, wears faster and irregularly. Tyres mounted in duals must be
matched so that the maximum difference between the diameters of the tyres
does not exceed 6 mm. This may be measured by using either a square or
matching stick. The larger tyre should always be mounted on the outside
position as road camber produces least loading on this position.
• Matched Inflation Pressures
It is important to ensure that both tyres on a dual tyre assembly have
matched inflation pressures. Mismatched pressures result in the
underinflated tyre wearing faster and irregularly, and the correctly inflated
tyre becoming overloaded, with an increase of heat and probability of premature tyre failure.
Forkhoist and Industrial Vehicles
Only purpose-designed industrial tyres that are approved by the vehicle
manufacturer and approved for the rim specification may be fitted.
For vehicles such as agricultural tractors and other low-speed vehicles where
radial and crossply tyres are fitted to the same vehicle, it is recommended
that the radial and crossply tyres be fitted to different axles and not mixed
on the same axle.
Forklift Industrial Tyres And Rims
This section outlines some of the requirements to be met by the forklift
owner/driver, the tyre fitter and the tyre/rim supplier.
Safety Rules
1
Always remove valve core and fully deflate forklift tyres prior to
removing the wheel nuts, especially on divided or bolt-together
Health and Safety Guidelines for Tyre Fitters 25
rims. When reassembling divided/bolt-together rims, where possible, ensure the rim bolt-together bolts are fitted with the bolt heads
facing outwards. This practice helps differentiate between the
forklift wheel nuts and the rim bolt-together bolts.
Never try to remove
the split rim fastening
nuts instead of the
wheel fastening nuts
— this has caused
fatalities.
2
Always follow industry-approved safety precautions for deflation,
removal, fitment, inspection and inflation of pneumatic tyres.
Always use the correct tools and safety equipment when servicing
forklift tyres. For guidance, see the previous two pages.
3
Always obtain the correct information for the rim or tyre from the
product manufacturer, or their designated representative. All
reputable manufacturers produce specification information on their
products.
4
Always consult the forklift manufacturer before altering any tyre
specification on a forklift. You must ensure the rated load carrying
capacity and stability of the forklift will not be affected.
ACCIDENT CASE
Divided wheel flew apart
A worker was replacing the outside wheel of a dual-wheel assembly on
a forklift. He noticed that the nuts of the six bolts holding the two halves
of the divided wheel together were round the wrong way and the
wheel couldn’t fit properly. He attempted to remove the bolts one at a
time without deflating the tyre. The rim blew off and struck him on the
forehead. He died in hospital 9 hours later. The wheel had a warning
about this practice stamped on it.
General Requirements
After deflation and tyre removal, clean and inspect rim and components for
cracks and deformation. If in doubt, discard rim assembly. Check nuts, bolts
and washers used in divided or bolt-together rims. If any are damaged,
always replace them as a set with the correct grade and size.
Never mix and match multi-piece rim components. Always ensure that all of
the components are correctly fitted to the rim when reassembling. The bead
seat (or advance) band must be fitted, if the rim is designed to have one. If
the rim is designed to have a bead seat band, and it is missing, this is a
valid reason to reject the rim.
Most divided rims are only rated to 690 kPa (6.90 bar = 100 psi). This
makes them unsuitable for radial forklift tyre fitment due to their higher
inflation pressure requirement of 900 to 1000 kPa (9.00 to 10.00 bar = 130
to 145 psi). Only rims certified for 1000 kPa (10 bar = 145 psi) cold inflation
pressures are suitable for radial forklift tyre fitment.
Health and Safety Guidelines for Tyre Fitters 26
KEY POINTS
Only industrial forklift tyres, normally marked NHS (nonhighway service), are
suitable for fitment to forklifts.
Truck tyres, even though they may have the same tyre size and ply rating,
must not be fitted.
Example:
10.00 - 20 14-ply truck tyre at 700 kPa (7.0 bar = 102 psi) is rated to carry a
load of 2575 kg per tyre in a dual fitment situation.
10.00 - 20 14-ply forklift tyre at 700 kPa, due to its heavier construction, is
rated to carry a load of 5640 kg per tyre in a dual fitment situation.
The sum of the load capacity of all the tyres fitted to a forklift must not be
less than the gross mass of the forklift (this includes the weight of the
forklift and its maximum rated load) at the maximum speed of which the
forklift is capable.
Operational requirements as set by the forklift manufacturer must be met,
such as correct tyre type, inflation pressure, ply rating and rim type.
Most forklift manufacturers rate their forklifts, for stability and load-carrying capacity on industrial cross-ply pneumatic tyres, industrial cushion or
resilient tyres. Before altering the tyre construction type, for example, crossply to radial, the forklift manufacturer must be consulted, as this may affect
the stability or load-carrying capacity of the forklift.
Cushion solid (resilient) tyres can be fitted to all forklift rims. Irreparable
damage can be caused to rims and tyres if correct tyre to rim fitment
techniques are not adhered to. Proper pressing equipment is required to
ensure damage-free fitment of tyre to rim.
When replacing worn or damaged forklift rims, ensure that the replacement
rim is designed to carry the load and pressure of the tyre. Never add or
remove an attachment from, or otherwise modify, a forklift rim. Never weld
a cracked rim. Never apply heat, weld or brazing to a rim, unless the tyre
has been removed, and approval has been received from the rim manufacturer. Modification or heating of a rim or one of its components may
weaken it so that it cannot withstand forces created by inflation or operation. Components of multi-piece rims wear during their service life. Do not
replace worn or damaged components with new ones and fit to a worn rim
base. Fitting new components onto an old rim base could cause DEATH or
INJURY because the new components may not lock in or seat properly. If in
any doubt, for safety’s sake, reject the rim.
Tyre Wear Limits
There are no national or international standards for the limits of tyre wear
for forklifts, but some manufacturers give guidance which is usually re-
Health and Safety Guidelines for Tyre Fitters 27
stricted to their own products. The tyre manufacturer’s recommendations
should always be followed.
Cushion solid (resilient) tyres have a 60J or safety line around the circumference. This safety line signifies the maximum wear limits of the tyre.
Pneumatic tyres should be inspected daily for cuts, cracks and wear. If any
part of the tyre carcass is exposed, the tyre must be replaced immediately.
Health and Safety Guidelines for Tyre Fitters 28
6: Demounting Tyres
Vehicle jacked with
wheel off — ready for
tyre replacement.
1
Before deflation, read and chalk the tyre pressure on the tyre wall.
Take special note of any tyre with 80% or less of recommended
pressure.
2
When any wheel or tyre is in a damaged condition, remove the
valve core completely to deflate the tyre before you take the wheel
off the vehicle.
3
Don’t remove any tyre from a wheel rim unless you have removed
the valve core and are sure the tyre is fully deflated. Remove both
valve cores from a dual assembly.
4
Always exhaust all air from a single tyre, and from both tyres of a
dual assembly, before you remove any rim or wheel components
such as nuts and rim clamps.
5
6
Always check the valve stem, by running a piece of wire through
the stem to be sure that it is not plugged.
Always wear suitable eye protection while removing tyres from
rims.
Removal of Common Assemblies
Car, Van and Tractor Tyres — Well-base Rims
1
2
3
Remove valve core and completely deflate tyre.
4
5
Lubricate the rim flange and tyre bead areas, using an approved
tyre bead lubricant.
6
Remove the tube if fitted.
Disengage the valve core from the rim (tube type).
Unseat both tyre beads using the correct hand tools or with pneumatic, hydraulic, or mechanical equipment. Be sure to follow the
instructions supplied.
With the narrow rim ledge facing upwards, pry the top tyre bead
over the top rim flange, starting at the valve area. Be careful not
to damage the tyre beads by using excessive leverage.
Health and Safety Guidelines for Tyre Fitters 29
7
Remove the bottom bead over the top rim flange.
Light Truck, Truck Tyres - Multi-Piece Rims
1
Remove the valve core and completely deflate the tyre. This must
always be done before removing a wheel from a vehicle or removing
a tyre from a wheel. This applies to both tyres in a dual assembly.
Run a piece of wire through the valve stem to ensure it is not
plugged.
2
3
Lay the assembly on the ground with the lock ring assembly facing
upwards.
4
5
6
7
8
Use only approved tyre bead lubricant to assist with the bead
breaking operation.
Unseat the top facing bead with the appropriate tools or equipment. Follow the instructions supplied with equipment when using
pneumatic, hydraulic, or mechanical equipment to break the bead
seats.
Be careful to use the correct levers and not to distort loose flanges
and lock rings when removing from the rim.
Push the valve stem inside the rim where possible.
Turn the wheel assembly over and unseat the tyre bead.
Remove tyre away from rim.
Demounting Off the Vehicle
1
Remove any water ballast or air from the tyre. Remove the valve
core and completely deflate the tyre. Lay the assembly on the floor
with the narrow ledge at the bottom.
Remove the valve core.
Health and Safety Guidelines for Tyre Fitters 30
2
Drive a bead unseating tool between the tyre bead and rim flange,
being careful not to damage the tyre bead area. After the bead has
been released completely around the tyre, turn the tyre and rim
over and repeat the bead unseating procedure with the narrow
ledge up.
3
With the narrow ledge on top, thoroughly lubricate the rim flange
and tyre bead area with an approved tyre lubricant or a thin
solution of vegetable oil soap in water. (Never use antifreeze,
silicones or petroleum-based lubricants.)
4
Force the part of the bead that is directly across from the valve
into the well. Starting at the valve, pry the top bead over the rim
flange using two 18-inch-long tyre levers or the tyre mounting/
demounting tool. Continue by taking small bites to avoid damage to
the bead until the top bead is completely over the rim flange.
Unseat the bead.
Lubricate the rim
flange and tyre bead
area.
Pry the bead over the
rim flange.
Health and Safety Guidelines for Tyre Fitters 31
Break the second bead.
Lift the bead over the
flange.
5
Bring the assembly to an upright position and pull the tube out of
the tyre (if it is tubed). If only the tube requires repair or replacement, this can be removed, repaired, and replaced in the tyre
without removing the tyre completely from the rim.
6
Thoroughly inspect the inside of the casing for damage or other
foreign material. Remove any remaining fluid from inside the tyre.
7
To completely remove the tyre from the rim, turn assembly over so
the narrow ledge is down.
8
Lubricate the second tyre bead and rim flange. Be sure the one
side of the bead still on the rim is in the rim well and insert the
tyre levers or the mounting demounting tool under the opposite
side of the bead.
9
Work the rim slowly out of the tyre by taking small bites alternately using both tyre levers. Alternatively, use the mounting/
demounting tool to lift the bead over the flange.
10
Remove the tyre from the wheel.
Remove the tyre.
Health and Safety Guidelines for Tyre Fitters 32
Demounting On The Vehicle
(Some steps for the following procedure may require two persons on larger
size tyres)
1
Jack up the vehicle, then deflate the tyre by removing the valve
core housing. If necessary position the tyre for emptying any fluid
fill from the tyre. For tube-type tyres, remove the rim nut and push
the valve through the valve hole.
2
After the tyre is completely deflated, place a hydraulic “bead
unseating” tool between the tyre bead and rim flange and force the
bead off the bead seat. Be careful not to damage the tyre’s bead
area. The beads should be unseated on both sides of the rim.
3
Thoroughly lubricate the tyre bead area and rim flange with an
approved tyre mounting lubricant or a thin solution of vegetable oil
soap in water. (Never use antifreeze, silicones or petroleum-base
lubricants because this will damage the tyre.)
4
Force the part of the bead that is directly across from the valve
into the well. Starting at the valve, pry the top bead over the rim
flange using two 18-inch long tyre levers or the tyre mounting/
demounting tool. Continue by taking small bites to avoid damage to
the bead until the top bead is completely over the rim flange.
5
Bring the assembly to an upright position and pull the tube out of
the tyre (if it is tubed). If only the tube requires repair or replacement, this can be removed, repaired, and replaced in the tyre
without removing the tyre completely from the rim.
6
7
8
Thoroughly inspect the inside of the casing for damage or other
foreign material. Remove any remaining fluid from inside the tyre.
9
Work the rim slowly out of the tyre by taking small bites alternately using both tyre levers. Alternatively use the mounting/
demounting tool to lift the bead over the flange.
10
Remove the tyre from the wheel.
To completely remove the tyre from the rim, turn assembly over so
the narrow ledge is down.
Lubricate the second tyre bead and rim flange. Be sure the one
side of the bead still on the rim is in the rim well and insert the
tyre levers or the mounting demounting tool under the opposite
side of the bead.
Health and Safety Guidelines for Tyre Fitters 33
7: Repairing Tyres
Using a tyre changing
machine.
An electrohydraulic
semi-automatic tyre
changer to demount
and mount truck, bus,
tractor and earth
moving equipment
tyres.
1
Tyres which contain a substance additional to compressed air must
be treated with caution. Flammable examples are gas propellant
used to pressurise latex for emergency puncture repair, or methylated spirits used as antifreeze in tractor tyres.
2
Tyre sealants and repair materials are to be used strictly according
to manufacturers’ instructions. Tyre sealants used to seal tyres
against air loss require special steps during examination for punctures.
3
Clean and carefully examine all flanges, locking rims and rim
gutters. Reject any that are damaged, distorted, cracked or broken.
They must not be reused under any circumstances.
4
Don’t interchange rim parts. Although they may look alike, variance between rims of different types makes part-mixing dangerous.
Side rings, flanges and lock rings of different types may appear to
be correctly seated but actually have wide gaps which make them
dangerous. Check markings.
5
6
With tyres which have been run at low pressure, look especially for
sidewall damage. Reject tyres with dark lines or broken steel cords.
7
8
9
10
11
12
Always use an approved tyre bead lubricant when fitting tyres.
Check that the tyre is in sound condition, both inside and outside,
and be sure to use only the correct size and type of tube, flap,
flange and locking ring.
After assembling a wheel and tyre, check the positioning of loose
flanges and the locking ring. Don’t inflate until they are right.
Before inflating, be sure that you know the correct pressure for the
size and ply rating of the tyre. Don’t guess.
Use a cage guard, or if a cage guard is not available, use a suitable
restraining device.
Wear suitable eye protection before starting assembly. This is
important!
If you have any doubts about what to do, or about what you have
done, ask your supervisor, or check the appropriate manual or wall
chart before inflating.
Health and Safety Guidelines for Tyre Fitters 34
Zipper Hazard
The zipper rupture is not uncommon and potentially is one of the most
dangerous that tyre service persons are frequently exposed to. A zipper is
the name given to the bursting of a radial truck tyre sidewall circumferentially in the mid to upper sidewall area.
A tyre with a zippered side wall.
The steel-belted radial truck tyre has a carcass which consists of one single
body ply. This ply is made up of steel wires or cables, each consisting of a
number of filaments wound to provide a flexible yet strong sidewall. Steelbelted radial truck tyres, like other tyres, are designed to deflect within an
optimum range when loads, pressures and road surface variations are
imposed. When, however, a steel-belted radial truck tyre is run underinflated, the deflection is significantly increased, concentrating stress in one
particular area of the sidewall. This has the effect of causing the body ply
wires or cables in the sidewall to bend at angles far greater than they are
designed for, or capable of, and they begin to break.
Eventually, only a small number of wires or filaments remain intact within
the area. This is when the zipper is at its most dangerous state.
In this state, either continued deflection or an increase in pressure will
cause the tyre to explode.
KEY POINT
When a zipper forms, during inflation, the weakened sidewall will start to tear
at the point of weakness, and burst with a long narrow opening. Wire and
rubber shrapnel will leave the tear driven by escaping compressed air. When
the zipper occurs at higher pressures, whole tyre and wheel assemblies can
be thrown in any direction as the sidewall explodes.
A truck has been blown off its jack, and tyre servicemen blown across the
fitting bay. Injuries include penetration by wire shrapnel, deep into the arm of
one victim, and impact of thrown wheel assemblies with injuries requiring
hospital treatment. The zipper effect has already claimed the life of one tyre
worker in New Zealand.
Identifying the Hazard
So how do we recognise tyres with zipper symptoms? Symptoms are difficult
to detect, in fact, most people who experience zippers said that there were
no marks or indications on the inside or outside of the tyre.
•
Most tyres were known to have been punctured or flat before the
unzipping occurred.
•
A creaking/ripping noise occurred just before unzipping occurred.
•
Bulging was often not evident before unzipping occurred.
•
Pressures at which the zipper occurred ranged from as low as 20
psi up to 100 psi, with most zippers occurring between 60 - 80 psi.
Health and Safety Guidelines for Tyre Fitters 35
Any tyre which has a darkened line on the liner at the shoulder area, any
tyre which creaks or clicks when flexing the sidewall, any tyre which shows
wavy or run flat type sidewall marks, any tyre which has been known to
have had a puncture or been run underinflated or overloaded, is a risk. If
you are at all suspicious about a tyre, then get a second opinion before
mounting it. If in doubt, scrap it (with the customer’s permission of course).
Inspection
Often, potential zipper tyres will exhibit clues which singly or together may
indicate that the tyre has been run under-inflated and potentially may
unzip. Inspect carefully for the following:
Checking a side wall.
•
Fleet-check marking on the tyre showing a low pressure or flat tyre.
•
Bulges, distortion or buckling of the tyre sidewall.
•
Discolouration, wave marks, wrinkling, or crease marks on the
inner liner.
•
Protruding cords or wire filaments.
•
Any penetration through the liner and indications of under-inflated
use.
•
Any under-inflated use.
•
Any sidewall areas exhibiting soft or weak areas.
•
Any creaking, clicking, or popping noise.
Be aware, however, that tyres may unzip without any of the above indications being present and at any pressure. Tyres exhibiting any of the above
indications must not be inflated. Such tyres should have a warning tag
affixed or be rendered unusable by cutting the sidewall (with the customer’s
permission of course).
Deflating a Zipper
Should a tyre exhibit bulging, distortion, creaking or clicking noises, immediately:
1
2
Stop inflation.
Release the hose from the air supply.
Do not attempt to remove the hose from the valve stem until fully deflated.
Health and Safety Guidelines for Tyre Fitters 36
KEY POINT
Not all radial truck tyres with potential to zipper exhibit any of the above
clues. Accordingly, all radial truck tyres should be treated as potential
zippers.
Follow these basics:
•
Always inflate all truck tyres in a safety cage.
•
Remove tools away from the inflation area.
•
Remove the valve core for the first inflation.
•
Use a minimum 2-metre long hose with clip-on chuck and quick
release device at both ends.
•
Wear face masks and overalls with sleeves down.
•
Keep earmuffs off during inflation.
•
Turn radio down.
•
Listen carefully for any creaking, clicking noises during inflation.
•
Check the sidewalls externally at 20 kPa or 3 psi for any bulges or
distortion.
•
Stay out of the trajectory area.
Shaded areas are probable trajectories for wheel parts should tyres explode.
Roadside or Off-Site Servicing
Often servicing must be performed away from the tyre service bay or any
nearby safety cage. In such instances it is important that the tyre and wheel
assembly is restrained during inflation and to keep well clear of the trajectory. Restraint may take any one of these forms:
•
Use the fold-down safety cage if one is fitted to the service vehicle.
•
Restrain the tyre-wheel by lowering a tail-lift, if one is fitted. Be
aware that the tailgate may lift rapidly during an explosion.
Health and Safety Guidelines for Tyre Fitters 37
•
Slide the tyre wheel assembly under the service vehicle.
•
If none of the above are practicable, ensure that a substantial
vehicle is between the tyre and people in the area.
•
Bolt the tyre wheel assembly to the vehicle before inflating.
•
Keep out of the trajectory path.
Safety Rules for Road Side Servicing
1
2
3
4
5
Wear high-visibility vests.
If practicable, drive on to a lay by.
If it is not practicable to drive on to a lay by, pull off the road.
If it is not practicable to pull off the road, park the vehicle as far
left as possible, and put out warning cones and triangles.
If it is not possible to work safely because the vehicle is in an
unsafe position, call the police to manage traffic at the site.
Tyre Sealants
Tyre sealants is the name for three groups of products.
On-road tyre sealants
Photo: Using a
tyre sealant
These are intended to help retain air at the correct pressure, and must be
used according to the manufacturer’s specifications. A tyre sealant for onroad use must be able to maintain the balance of the tyre in highway conditions of high speed and raised temperature, and cannot be safely replaced by
sealant intended for off-road use.
When adding sealant to tyres, the tyre profile must be maintained, without
the weight of the vehicle being allowed to flatten the tyre. Failure to follow
this instruction may result in the tyre becoming damaged. Ensure when
using tyre sealants that you adhere strictly to manufacturers’ dosage instructions.
When using a tyre
sealant, always follow
the manufacturer’s
instructions.
Tyres treated with on-road tyre sealant which lose air should have a repair
done in accordance with NZS 5423:1996 Specification for repairing and
retreading car, truck and bus tyres or the LTSA Wheels and Tyres Rule.
Health and Safety Guidelines for Tyre Fitters 38
KEY POINT
When adding sealant to vehicle tyres, the tyre profile must be maintained.
The supplier’s instructions must be strictly followed.
Tyre sealants for off-road tyres
Tyre sealants for off-road tyres are for use at low pressure and low speed.
They are used to repair punctures in the tread, but not in the shoulder or
sidewalls of tyres.
KEY POINT
Tyre sealants for off-road tyres are for use at low speed.
Aerosol tyre sealants for temporary repairs
Temporary puncture repair tyre sealants for puncture repairs are blown
from an aerosol can. Manufacturers’ instructions must be followed. Their
main market appears to be car drivers who want inflation of a flat tyre to
enable continuing their journey without a wheel change.
Some tyre sealants for temporary repairs contain propane. The first fill of
propane in most cases will put the concentration of propane in the tyre
above the upper explosive limit. Re-inflation with air may reduce the concentration of propane to form an explosive mixture of air and propane in the
tyre. The tyre can then be compared with a bomb. An ignition source, such
as a reamer against steel wires in a radial tyre, may cause an explosion.
Temporary puncture
repair tyre sealants are
blown from an aerosol
can.
Tyre sealants for temporary repairs which use latex are nonflammable.
Tyre repairers should find out which tyre sealant was used for any temporary repair.
KEY POINTS
Check to see whether this tyre has been treated with an aerosol can sealant.
Tyres must be removed from the wheel for repair.
BEWARE OF PUNCTURED TYRES WHICH ARE STILL INFLATED.
Health and Safety Guidelines for Tyre Fitters 39
8: Tyre Mounting
Safety Precautions
WARNING
There is a danger of serious injury or death if a tyre of one bead diameter is
installed on a rim or wheel of a different rim diameter.
Always replace a tyre with another tyre of exactly the same bead diameter
designation and suffix letters. For example:
•
A 16-inch diameter tyre goes on a 16-inch diameter rim. Never
mount a 16-inch diameter tyre on a 16.1-inch diameter or 16.5-inch
diameter rim.
•
A 16.1-inch diameter tyre goes on a 16.1-inch diameter rim. Never
mount a 16.1-inch diameter tyre on a 16-inch diameter or 16.5-inch
diameter rim.
•
A 16.5-inch diameter tyre goes on a 16.5-inch diameter rim. Never
mount a 16.5-inch diameter tyre on a 16-inch diameter or 16.1-inch
diameter rim.
For the same reason:
•
Never mount a 26-inch diameter tyre on a 26.5-inch diameter rim.
•
Never mount a 30-inch diameter tyre on a 30.5-inch diameter rim.
While it is possible to pass a 16-inch diameter tyre over the lip or flange of
a 16.1-inch diameter or 16.5-inch diameter rim, it cannot be inflated enough
to position itself against the rim flange. If an attempt is made to seat the
tyre bead by inflating, the tyre bead will break with explosive force and
could cause serious injury or death.
To Determine Compatible Rim Width for Tyre Sizes
Measurement of rim
width and diameter.
1
Determine the vehicle’s actual rim width by measuring, in inches,
the distance between the vertical bead flanges as shown. A simple
ruler or yardstick may be used, as rims are manufactured in half
inch increments of width.
2
Check the tyre that came off the rim. Look on the rim for tyre size.
If you can’t read rim markings, check with the vehicle manufacturer or have a qualified person read the rim.
3
Rims for specialised applications require special tyres. The size
code of the rim must be checked for compatibility.
Health and Safety Guidelines for Tyre Fitters 40
Mounting Tyres
Compressed air lines must have a press button or similar type of hand
control. There must be at least 2 metres of air line between the hand control
and the chuck which clips on to the tyre valve. This is essential for your
safety: it keeps you out of the most dangerous area should anything go
wrong. Follow these steps for your own safety:
1
With a suitable lamp, examine the tyre wall for any bulging due to
damage. Zippering walls may show signs of bulging. Reject any tyre
in which zippering is starting to occur. Turn down the workshop
radio and inflate the tyre, listening for popping noises which signal
ripping of cords in the tyre wall. Zippering is most likely in tyres
which have been run at low pressure. Ripping cords signal the start
of a zipper.
2
Inflate to about 20 kPa (3 psi), but definitely not above 35 kPa (5
psi). Then check that the tyre is properly centred on the rim and
that flanges and locking rings are correctly seated.
3
Remove the valve core and allow the tyre to deflate fully. Now,
place the tyre/wheel assembly into a safety cage or suitable restraining device, before inflating using a clip on chuck. Passenger
tyres fitted on passenger well-base rims may be inflated without a
safety cage.
4
Inflate to full pressure, standing away from the tyre, but still
listening for popping caused by zippering. Any zippering tyre shall
be rejected. After inflation, release the air pressure and allow the
tyre to deflate. You can now replace the valve core and inflate fully.
5
This is the stage where most accidents and the most serious injuries occur. In every accident notified to OSH, the dead or injured
person has not correctly used a suitable cage guard or restraining
device. Be sure, by a thorough examination, that it is safe to proceed to full inflation.
ACCIDENT CASE
Air hose left unattended
A tyre fitter left an open-ended air line attached to the valve of a
tractor tyre while he went to answer the telephone. The conversation
took longer than expected, and when he returned he realised the tyre
was dangerously over-inflated. As he removed the chuck from the
valve, the tyre exploded and he was thrown against the ceiling and
killed instantly.
6
While inflating on the vehicle, use an in-line gauge and control
device with at least 2 metres of hose between the control device
and clip-on chuck so that you can stand well clear.
Health and Safety Guidelines for Tyre Fitters 41
7
8
Attend to the air line the whole time that the tyre is inflating.
Never leave an un-monitored air line attached to a valve.
9
After running the vehicle for a short distance, wheel nuts should be
checked for tightness. Parts will seat naturally and torque on nuts
will drop, requiring them to be tightened to the correct specifications. This is essential; in the worst case the wheel will fall off.
Never hammer on an inflated or partially inflated tyre/rim assembly. It could fly apart and kill or seriously injure you or someone
else.
Mounting of Common Assemblies Tyres
Car, Van and Front Tractor Tyres — Well-Base Rims
1
2
3
4
5
6
7
8
9
Check that rim bead seats and flanges are in good condition and
not damaged or distorted.
10
Inflate to 35 kPa (5 psi) only, then check that the tyre is properly
centred on the rim. Don’t check the seating of the bead by standing
over the wheel, but from one side.
11
In the case of larger tractor tyres, you should put the assembly into
a safety cage or other suitable restraining device. If a safety cage is
impracticable to use, for example in the middle of a paddock with a
large tractor tyre, it should be possible to inflate the tyre with a
vehicle between the tyre and the service person. If you don’t, and
Be sure the tyre casing is undamaged and that there is no foreign
matter left inside the tyre.
Place the rim on the fitting machine or floor with the narrow rim
ledge facing upwards.
Check to see if the tyre has to be fitted a certain direction.
Lubricate both tyre beads with approved tyre lubricant.
Position bottom tyre bead over top rim flange, working tyre bead
into the rim well.
Insert tube if tube type.
Position top tyre bead over top rim flange, working tyre bead into
the rim well.
Before inflating, be sure of the correct pressure for the size and ply
rating of the tyre. Never exceed the maximum pressure shown on
page 56 of this booklet.
Health and Safety Guidelines for Tyre Fitters 42
the assembly comes apart during inflation, you are likely to be
killed or seriously injured.
12
If the tyre beads have not seated correctly at the recommended
pressure, STOP! Deflate the tyre. Free the beads and relubricate
them. Reinflate the tyre.
ACCIDENT CASE
Tyre bead not seated at low pressure
A mechanic was inflating a tractor tyre he had just fitted to the wheel
rim. He had difficulty getting the bead to seat against the rim and
asked an experienced workmate to help him. The tyre was marked
WARNING: NEVER EXCEED 35 PSI WHEN SEATING BEAD. As the man was
leaning over to examine it, the tube burst and the tyre was forced over
the rim, throwing him a metre in the air. He was struck by the rim and
died from his injuries. There was a suitable tyre cage metres away. The
pressure gauge fitted to the air line was not working and it was assumed later that the tyre may have been inflated to a pressure of 80
psi.
Light Truck, Truck Tyres — Multi-Piece Rims
1
Before you start, be sure that the flanges and locking rings are the
right size and are in good condition. Check for any damage, distortion or cracks with the rim, flange or lockring. Discard damaged
components. In most cases don’t try to repair or modify them — it
could kill you or those using the vehicle. Wheel repair is a specialised skill and advice must be sought when there is a doubt.
2
3
If the rim is a 4-piece flat-base type, ensure that the inner flange
ring has been fitted.
4
Insert the inner tube and flap. Partially inflate the tube to conform
to the tyre shape. Check the tube has not creased or pinched.
Attach a valve retrieval tool to the valve stem and thread the tool
through the valve hole.
5
6
Lubricate both tyre beads with approved tyre lubricant.
7
Fit the flange and lock ring into the correct seating position. DO
NOT use excessive force to fit the lock ring.
Check that the inside of the tyre is clean from foreign matter.
Place the rim on the ground with the lock ring side facing upwards. Mount the tyre over the rim locating the valve retrieval tool
stem through the rim valve hole.
Health and Safety Guidelines for Tyre Fitters 43
8
Inflate to no more than 35 kPa (5 psi) and check that the tyre is
properly centred on the rim. Check that the loose flanges and lock
rings are correctly seated.
9
Don’t stand over the wheel. Check the seating of the parts from the
side. Never attempt to correct the seating of the side and locking
rings by hammering, or by forcing the components while the tyre is
pressurised.
10
The assembly must be kept in the restraining device while it is
inflated to the recommended pressure and the tyre, rim and rings
are seen to be properly seated and locked. If they are not, then
deflate the tyre. The assembly may then be removed from the
restraining device and the components relubricated and repositioned. You should again inflate it to no more than 35 kPa (5 psi),
check it and then replace it in the restraining device for inflation
to the recommended pressure.
11
Multi-piece rim wheels also require special care because of their
weight. You should be careful that loose flanges and locking rings
do not drop on your fingers when lifting. Remember when rolling,
they are liable to veer off suddenly. Also the loose flange or locking
ring may move violently from one side of the rim to the other, so
keep your fingers clear.
Mounting off the Vehicle
Push the bottom bead
over the rim flange.
1
Lay the rim on the floor with the narrow
ledge on the top. Thoroughly lubricate the
tyre bead area and rim flange with an
approved tyre mounting lubricant or a thin
solution of vegetable oil soap in water.
(Never use antifreeze, silicones or petroleumbase lubricants because this will damage the
tyre.)
2
Push the bottom bead over the rim flange as
far as possible.
3
Use 18-inch tyre levers or the tyre mounting/demounting tool to
work the first tyre bead completely over the rim flange, taking
small bites and being careful not to damage the bead.
Work the first tyre bead
over the rim flange.
Health and Safety Guidelines for Tyre Fitters 44
Use tyre levers to
lever the top bead
over the rim flange
and down into the rim
well.
Place tyre/rim/wheel
on a safety cage or
other restraining
device.
4
5
If using a tubeless tyre, place the valve through the hole in the rim.
6
7
Thoroughly lubricate the tyre bead area and rim bead seats on both
sides of the tyre.
8
Place tyre/rim/wheel on a safety cage or other restraining device.
Wear face protection. Inflate the tyre (with the valve core removed)
to seat the beads. Do not exceed 245 kPa (35 psi). It is essential for
the operator to stand clear of the tyre. Check to see that both
beads are seated all the way around the tyre. If the tyre is tubetype, completely deflate (to allow repositioning of the tube) by
removing the valve core housing. For tubeless tyres, mounting
depends on how well the shape of the tyre has been maintained. If
the beads are in or near their moulded position, they can be seated
by inflating the tyre, through the valve spud. Where the beads have
been squeezed together, the use of an inflator ring (either horizontally or vertically) will be required to provide a seal between the
tyre bead and rim.
9
10
Check the tyre for evidence of potential zipper rupture.
Starting opposite the valve, use tyre levers to lever the top bead
over the rim flange and down into the rim well. Be careful to avoid
pinching the tube with tyre levers. Locking pliers may be used to
keep your place. When the bead is well started, lubricate the
remaining unmounted portion of the tyre bead and rim flange.
Taking small bites, spoon the tyre bead over the rim flange until
the final section drops over at the valve.
Centring the tyre on the rim is extremely important to prevent
broken beads. Use an extension hose with an in-line air gauge and
clip-on chuck.
Re-insert the valve core and re-inflate the tyre to the vehicle manufacturer’s recommended operating pressure. Remove from the
safety cage.
Mounting on the Vehicle — Agricultural
1
Thoroughly lubricate the tyre bead area and rim flange with an
approved tyre mounting lubricant or a thin solution of vegetable oil
soap in water. (Never use antifreeze, silicones or petroleum-base
lubricants because this will damage the tyre.)
2
Before placing tyre on rim, be sure valve hole of rim is at bottom
of wheel. To put the tyre on the wheel, place the inner bead over
the flange at the top. Be sure the bead is not hung up on the bead
seat, but that the bead is guided into the rim well, while the tyre
levers and/or rubber mallet are used to work the first bead over
Health and Safety Guidelines for Tyre Fitters 45
the rim. With the first bead on the rim, pull the tyre toward the
outside of the rim as far as possible to make room for the tube.
3
Before inserting a tube in a tube-type tyre, be sure the valve is at
the bottom of the wheel. Align the stem with the valve hole and
place the tube in the tyre, starting at the bottom. Place the valve in
the valve hole and screw the rim nut in place. Be sure that the
tube is well inside the rim before proceeding to the next step.
4
Relubricate the tyre beads and rim flange. In tube-type tyres the
tube should be partially inflated and base area that contacts the
rim should be lubricated to prevent localised stretching.
5
Starting at the top, use the tyre levers to lift the outer bead up and
over the rim flange. then down into the rim well. Be careful not to
pinch the tube in this operation.
6
After getting the first section of the outer bead into the rim well,
place one hand against that section to hold it and then pry the
remainder of the bead over the flange with the tyre lever in the
other hand.
7
With the valve stem at the bottom, lower the jack until the tyre is
centred on the rim. Centring of the tyre and rim assembly is
extremely important to prevent broken beads. Wear face protection.
Using an extension hose with an in-line air gauge and clip-on chuck
(with valve core removed), inflate the tyre to seat the beads. Do not
exceed 245 kPa (35 psi). It is essential for the operator to stand
clear of the tyre. Check to see that both beads are seated all the
way around the tyre. For tubeless tyres, mounting depends on how
well the shape of the tyre has been maintained. If the beads are in
or near their moulded position, they can be seated by inflating the
tyre, through the valve spud. Where the beads have been squeezed
together, the use of an inflator ring (either horizontally or vertically) will be required to provide a seal between the tyre bead and
rim.
8
Raise the vehicle and rotate wheel assembly to have the valve at
the top. If the tyre is tube-type, completely deflate by removing the
valve core housing. Re-insert the valve core and re-inflate the tyre
to the recommended operating pressure.
Health and Safety Guidelines for Tyre Fitters 46
9: Rim and Wheel
Types
Drop Centre or Well Base Rim
Flat base rim (rear)
and drop centre rim
(front).
Drop centre rim.
The drop centre rim is of one-piece construction with a 50 to 150 taper in
the bead seat on both sides. This is the rim used for tubeless tyres and it
can be mounted on medium and heavy trucks, commercial trailers and
buses.
Flat Base Rims
Two-piece and three-piece flat base rims.
The flat base rim is made in either two- or three-piece construction and is
designed for use with tube-type tyres. This is the rim commonly used on
medium and heavy trucks, trailers and buses.
Health and Safety Guidelines for Tyre Fitters 47
Wide Base One-Piece Rim
Wide-base rim.
Wide-base rim.
The wide-base rim is also of one-piece construction, with a 50 or 150 taper in
the bead seats. It is made for the super-single type of tyre, where one unit
replaces dual tyres. They are used on light, medium and heavy trucks and
trailers. The rim is measured in width (W) and distance (D). The width is
that dimension between the side flanges, while the diameter is measured
from where the heel of the bead fits on the rim. It is absolutely imperative
to use the right size rim for the tyre, and to use a rim that has the load
rating to carry the tyre that is to be used. To be sure of this, always check
the rim charts and load and inflation tables.
Multi-Piece Rims
Multi-piece rim.
Multi-piece rim.
A multi-piece rim is any rim with two or more parts, one of which is a
locking ring that holds the inflated tyre on the rim by interlocking components.
Health and Safety Guidelines for Tyre Fitters 48
Semi-Drop Centre Rim
The semi-drop centre rim is a two-piece rim with a base and side ring. The
semi-drop centre design makes tyre mounting easier. These rims have a 50
tapered bead seat on both sides and are used primarily for light trucks.
Semi-drop centre rim.
Semi-drop centre rim.
Divided Wheels
Divided wheels are those wheels in which the rim is in two halves which are
bolted together. They are most often fitted to barrows, trolleys, implements,
trucks or forklifts. However, there are some models of small Japanese cars
and trucks with divided wheel rims. Particular care must be taken not to
unfasten the rim clamping nuts while the tyre is still inflated. The clamping
nuts are generally painted red, but this may not always be so.
It is essential that every divided wheel has the tyre fully deflated and the valve
removed before being removed from the vehicle. This is to prevent any chance
of injury if the wrong nuts are undone.
Several accidents reported to the Occupational Safety and Health Service of
the Department of Labour have occurred because the wrong nuts were
removed from inflated wheels, resulting in serious injury. Similarly, when
inflating a tyre, you should be certain that the clamping nuts are fully
tightened first.
Divided wheel.
Health and Safety Guidelines for Tyre Fitters 49
10: Off-the-Vehicle
Wheel Balancing
A computerised off-thecar electronic wheel
balancer.
Ensure that the wheel
has stopped rotating
before attempting to
handle the wheel
1
Ensure the balancing machine adapter is correctly and securely
fixed to the tyre/wheel assembly. This is particularly important for
wire wheel adaptors.
2
3
4
5
Carefully lift the tyre/wheel assembly on to the balancing machine
spindle.
6
7
8
9
10
11
Don’t wear any loose clothing or jewellery that could be entangled
when the wheel is rotated.
Securely tighten the adapter collet.
Check the machine before starting and ensure that there are no
loose parts or tools on it.
Remove any stones or extraneous materials from the tyre tread as
they may fly out when the wheel is rotated. (The machine should
be guarded to protect the operator).
Don’t allow anyone near the machine while the tyre/wheel assembly
is rotating.
Don’t touch the tyre/wheel assembly while it is rotating.
Be sure that balance weights are securely clipped or stuck to the
rim before checking any residual imbalance.
If magnetic weights are used to determine static imbalance, remove
them before starting the machine.
Ensure that the wheel has stopped rotating before attempting to
handle the wheel or secure the adapter collet.
Health and Safety Guidelines for Tyre Fitters 50
11: On-the-Vehicle
Wheel Balancing
Excessive speed in a free-running, unloaded tyre can cause it to zipper or
explode from extreme centrifugal force. If drive wheels must be balanced on
the car, follow these precautions:
1
2
3
4
Chock the wheels to prevent the vehicle from moving.
Be sure the wheel is properly supported so that vibration will not
dislodge the axle support and allow the vehicle to fall.
Make sure people are clear of the areas in front of and behind the
vehicle.
On vehicles with a standard differential, put the transmission in
top gear or drive and spin the wheel by gradual acceleration to a
maximum of 65 km/h (40 m.p.h.) on the speedometer. Because of
the differential, this is 130 km/h (80 m.p.h.) wheel speed with one
wheel off the floor, or double the speedometer reading. Never rev
the engine.
ACCIDENT CASE
Speeding tyre zippered apart
A retread tyre had been fitted on the rim and then inflated to 90 psi,
then placed on the outside of a dual wheel, which was rotating to
centre the rim and tyre. To centre the wheel, the fitter arranged for the
jacked wheel to be rotated under engine power to establish wheel
centrality.
While the person in the cab controlling the throttle kept indicated
speed to 80 kph, with one wheel stopped on the ground, and one
wheel turning under power, the turning wheel rotated at the equivalent of 160 kph. Differential operation always means that with one
wheel stopped, while the other turns, the indicated speed will be one
half turning speed. The tyre zippered, with part of the rubber hitting the
fuel tank then the left side of the head and shoulder of the tyre fitter.
He was taken to hospital, where he died of injuries.
Possible effect for differential
Vehicle manufacturers should be consulted as the differential side
gears are spinning at a much higher speed than is the case in
normal service and this may have warranty and safety implications.
Health and Safety Guidelines for Tyre Fitters 51
In normal circumstances, side gears rotate at a very slow speed to
compensate for the slight speed difference between left and right
wheels on an axle due to different tracks when going round corners, slightly different tyre diameters, etc.
Four-wheel drive vehicles
Some four-wheel drives are essentially two-wheel drive, normally
rear, in normal on-road driving circumstances. Off-road, however,
four-wheel drive can be selected and both front and rear axles now
drive. Off-road the vehicle is driven at low speed as a centre differential is not fitted to allow for slightly different propeller shaft
speeds, with wheel slippage on off-road terrain compensating. For
on-road use, some are fitted with aftermarket free-wheeling hubs to
disconnect the drive between the front wheels and front differential. This allows the vehicle to be driven on road without driving
the front axle — reducing mechanical drag and fuel consumption.
This arrangement, however, could lead to dangerous circumstances
for the unwary, dependant on combinations selected and wheels
raised, with vehicles literally being driven off jacks and chocks if
the wrong combination is selected. The comments above relating to
differential gears overreving also apply.
Permanent four-wheel drive
These vehicles have a centre differential which is intended to allow
for slight speed differences between front and rear propeller shafts
in normal driving. Stopping one propeller shaft completely and
sending all drive through the other vastly overrevs the centre diff
side gears. In this circumstance, it is worse than the standard axle
(refer comment above) as speed has not been reduced by
crownwheel and pinion gearing, which is nominally about 3 to 1.
These centre differentials can also be locked, creating a similar
situation to the two-/four-wheel drive vehicle, which could also lead
to dangerous circumstances for the unwary, with vehicles literally
being driven off supports and chocks.
The comments above relating to each axle differential also still
apply.
5
If vibration indicates a need for balancing, this will be indicated at
speeds in the 50-65 km/h (30-40 m.p.h.) range on the speedometer,
i.e. 100-130 km/h (60-80 m.p.h.) road speed. This is the maximum
speed for dynamic balancing.
6
If the vehicle has a limited slip differential, keep both wheels off
the floor. Gradually accelerate to a maximum of 130 km/h (80
m.p.h.) on the speedometer, which is also 130 km/in (80 m.p.h.)
wheel speed.
Health and Safety Guidelines for Tyre Fitters 52
12: Balancing Truck
Assemblies
The following procedures must be followed when handling truck assemblies:
Take care when lifting
truck assemblies on
and off the balancing
machine.
1
2
3
4
5
6
7
8
9
10
Handle truck assemblies carefully when lifting them on and off the
balancing machine. They are often too heavy for one person to lift.
Remove any stones or other loose material from the tread of the
tyre. It could fly out when the machine is started.
Secure the adapter plate to the balancing machine spindle. Place
the lock pin in position.
Roll the assembly on to the lifting frame and lift carefully.
Secure the assembly to the wheel adapter plate while the weight is
still fully supported by the lifting frame.
Remove the lifting frame to a safe place where it is not an obstruction.
Secure new balance weights on the rim flange.
Place the balance arm mechanism in a safe place.
Place the lock pin in position before attempting to loose any wheel
adapter nuts.
Support the weight of the assembly on the lifting frame while
removing the wheel adapter nuts.
Health and Safety Guidelines for Tyre Fitters 53
13: Roadside Tyre
Repairs
I
t is best if tyre repairs are carried out in a fully equipped workshop but
there are times when they must be done at another work site or on the
roadside. It is very important never to take chances with safety in such
situations.
Always use road
marker cones and
wear a high-visibility
vest when carrying out
roadside repairs.
1
If the work site does not have a suitable cage guard or restraining
device, then one must be taken to the site or roadside. If a suitable
cage guard or restraining device are not available, then less safe
options are to place the wheel under the vehicle for inflation, or to
bolt the wheel in place on the vehicle before inflation.
2
3
4
5
6
7
8
9
Before you begin work, set up road marker cones round the roadside work area.
10
When the inner wheel of a dual assembly has to be removed for
repair, then the outer wheel, where possible, should also be deflated before removal from the vehicle. Fatal accidents have occurred when this has not been done.
11
Never introduce a flammable substance before, during or after
mounting.
Chock wheels on the opposite side of the vehicle before you place
the jack in position.
Regardless of how hard or firm the ground appears, put hardwood
blocks under the jack. Use axle stands where possible.
Always wear your eye protection and a high-visibility safety vest if
working on a roadside.
Stand clear when deflating. Ensure tyre is properly deflated by
removing the valve core.
Stand to one side when you use hydraulic pressure demounting
tools.
Be particularly careful to clean all dirt and rust from lock rings
and gutters, otherwise lock rings will not seat properly.
Discard any components that are cracked, badly worn, damaged,
bent, repaired or pitted from corrosion. When the condition of any
component is in doubt replace it — even if this means a delay in
obtaining new parts. Remember, if weakened parts give way during
inflation, you are likely to be killed or seriously injured.
Health and Safety Guidelines for Tyre Fitters 54
12
Don’t sit on, stand in front of, or stand over a tyre and rim assembly that is being inflated.
KEY POINT
Tyre service personnel required to change wheel assemblies by the roadside
should take extra care by following the points set out in 2, 3, 4, 5, 6 and 9
above.
Health and Safety Guidelines for Tyre Fitters 55
14: Tyre Inflation
Pressures
Never inflate above the pressures recommended by the tyre and wheel rim
manufacturers. Maximum pressures may be stamped on the sidewalls of
truck and light truck tyres. In practice, the following maximum pressures
should not be exceeded:
MAXIMUM INFLATION PRESSURES
All car tyres
322 kPa
(46 psi)
All van tyres except 8-ply
420 kPa
(60 psi)
Light truck
560 kPa
(80 psi)
Motorcycle tyres
280 kPa
(40 psi)
Tractor, front
280 kPa
(40 psi)
Tractor, rear
245 kPa
(35 psi)
Heavy truck
895 kPa
(130 psi)
Space saver tyres
420 kPa
(60 psi)
Industrial and heavy earthmoving tyres
Consult manufacturer’s.hand book
For passenger vehicles, look in the manufacturer’s tyre digest, or check the
load and inflation chart.
Free Air Dispensers
Air pressure available at free air dispensers should be limited unless tyre
inflation is under the control of an employee of the company offering free
air, for example the service station. The pressure could be limited to say 275
- 420 kPa (40 - 60 psi), i.e. a pressure unlikely to cause a tyre to rupture,
which would cover most users. If a customer wanted to pump a tyre to a
higher pressure, a staff member could increase available pressure from a
regulator only accessible to the staff member. Some service stations are
adopting this approach now.
Signage could simply say that: ‘Pressure available is limited to (275 - 420
kPa (40 - 60 psi)). If higher pressure is required, please refer to one of our
forecourt staff’. It could also refer the owner to the vehicle’s owner/driver
handbook for appropriate tyre pressures, or warn of pumping up tyres that
have been run flat for a period. The sign should be simple, however, if it is
to be read or comprehended.
Air pressure at free air
dispensers should be
kept to a safe limit.
Health and Safety Guidelines for Tyre Fitters 56
15: Use of Jacks
Always jack vehicles
on a hard, flat
surface.
1
2
3
4
5
All jacks must be checked for safe and efficient operation regularly.
6
7
8
9
10
Attach a warning card to the vehicle’s steering wheel or driver’s
door.
Always jack vehicles on a hard, flat surface, never on soft or uneven ground.
If you are working on the front wheels, chock the rear wheels and
put the park brake on.
Always use the jack safety catch.
When a wheel is removed, axle stands or blocks must be placed
under the axle. Always use axle stands where practicable. If using
hardwood blocks, use only clean blocks of a regular shape — not
dirty, greasy, misshapen or split blocks.
Make sure no one is inside a vehicle being jacked up and no one
enters or leans against it while raised.
Keep bottle jacks upright at all times.
Chock appropriate wheels (diagonally opposite to the wheel to be
removed).
Remove key from the ignition.
Bottle jacks must be
kept upright at all
times. Blocks of solid
hard wood are used to
give extra height to
the jacks.
Health and Safety Guidelines for Tyre Fitters 57
16: Tyre Safety Cages
A
ll tyres on split-rim wheels, and detachable flange wheels, must be contained by a cage guard or other suitable restraining device when being
inflated after being dismantled or repaired. All truck, bus, grader, tractor,
forklift and other tyres which have a large volume, or are inflated to high
pressures, must be contained by a cage guard or other suitable restraining
device when being inflated after being repaired or otherwise removed from
the wheel. It is strongly recommended that all tyres, including wheelbarrow
tyres, be inflated within a suitable restraint. There have been serious accidents even with these smaller types of tyres. Cage guards or restraining
devices showing damage or excessive corrosion should be repaired or replaced.
Car wheels and tyres are of strong construction have small internal air
volume and do not require high pressures. Car tyres pose minimal risk to
the serviceperson, and if correct fitting procedures are adhered to then
ruptures will not happen. Beware of divided wheels on small Japanese cars
— see page 00. However, car tyres should be inflated with the jaws of the
tyre fitting machine restraining the wheel.
Tyre cages should be anchored in workshops, that is they should be bolted
to the floor or restrained to minimise movement.
Examples of tyre
cages for permanent
installation. The
standard design can
be manufactured in
different sizes to suit
tyres fitted by the
customer.
Health and Safety Guidelines for Tyre Fitters 58
17: Identifying
Vehicles Fitted with
Airbags
A
ir bags are found in many of the vehicles sold in New Zealand since 1993.
They vary from single driver’s side air bag to the multiple air bag systems.
As tyre fitters you must be aware of vehicles that have air bags fitted, to
avoid accidentally deploying them. Accidental deployment may:
•
Cause serious injury or even death; and
•
Cost your organisation a lot of money to replace the air bag and
associated mechanisms.
Ways of Identifying Vehicles Fitted with Air Bags
There are two types of air bag operating systems, mechanical and electronic.
Most vehicle manufactures identify their air bag systems extremely well,
with dash warning lamps, and labels positioned in view of driver and passengers and engraved in the steering wheel and/or dash panel, as shown
below:
The owner’s handbook may also show that an air bag system is fitted.
Labels
Labels are situated at various locations on the vehicle to show that the
vehicle is equipped with Supplementary Restraint Systems (SRS) (air bags).
The following shows a sample of labels you may come across, indicating that
the car is equipped with SRS.
Health and Safety Guidelines for Tyre Fitters 59
On the windscreen.
On the front pillar or maybe on
the sun visor.
In the engine compartment, or underside of the bonnet.
KEY POINT
Some vehicles with air bags may not be easily identified. There is an aftermarket airbag system available in New Zealand. If you suspect a vehicle has
an air bag but are not, sure ask your supervisor.
Dash warning lamps
A dash-warning lamp is used only on systems that are electrically controlled.
The warning lamp may have different words or symbols depicting air bag
presence, depending on the manufacturer.
Safety when dealing with air bags
We cannot overemphasise safety when dealing with a vehicle with an air bag
system. These systems are controlled by the Explosives Act 1957 and should
be treated like a loaded shotgun with the safety catch OFF.
However, providing you take some simple safety precautions, you should not
have too many problems with them.
KEY POINT
When working on a vehicle with an air bag, don’t assume you are safe just
because the battery is disconnected.
Health and Safety Guidelines for Tyre Fitters 60
Personal Safety
Safety precautions include:
1
2
Be aware of vehicle safety systems, and their function. Electronic
air bags have a dash warning lamp; mechanical air bags do not.
3
When working around the steering wheel and the areas of the
passenger’s side air bag (if the vehicle is fitted with dual air bags),
be aware of the air bag systems and keep your face away from the
air bag deployment range. Do not probe electrical wires as this
could discharge the air bag system and seatbelt pretensioners.
4
5
Do not remove the steering wheel without first asking for help and
advice.
When working around the front wheels of a vehicle, be careful not
to bang and or knock the sensors as this could cause air bag
deployment.
Do not bang the steering wheel.
KEY POINT
When working around an air bag system, remember that they are explosive
and they deploy at speeds ranging from 280 to 480 kph and develop approximately 360 bhp, all this within 10-12 thousandths of a second.
The Costs of Accidentally Deploying an Air Bag
Replacement, air bags can cost a lot of money in fact thousands of dollars,
but by accidental deployment they can cause other damage as well, including:
•
Smashed front screens;
•
Burnt steering wheel;
•
Interior clean up;
•
Dash replacement in some vehicles.
Then there are the problems for your employer, such as explanations to
customers, parts replacement costs, down time for business, and the worst
thing of all — personnel injury or even death.
FINALLY
•
Take all proper safety precautions when working on a vehicle
equipped with air bags.
•
Remember to think safety all the time.
Health and Safety Guidelines for Tyre Fitters 61
18: The Employer’s
Responsibilities
T
he Health and Safety in Employment Act 1992 requires employers to take
all practicable steps to ensure the safety of employees while at work. In
particular, employers are required to take all practicable steps to:
The law requires
mployers to take all
practicable steps to
ensure the safety of
employees while at
work
(a)
Provide and maintain a safe working environment;
(b)
Provide and maintain facilities for the safety and health of employees at work;
(c)
Ensure that machinery and equipment is safe for employees;
(d)
Ensure that working arrangements are not hazardous to employees;
and
(e)
Provide procedures to deal with emergencies that may arise while
employees are at work.
Employers have responsibilities with regard to significant hazards in the
workplace.
(a)
Where practicable, the hazard must be eliminated.
(b)
If elimination is not practicable, the hazard must be isolated.
(c)
If it is impracticable to eliminate or isolate the hazard completely,
then employers must minimise the likelihood that employees will be
harmed by the hazard.
Where the hazard has not been eliminated or isolated, employers must,
where appropriate:
(a)
Ensure that protective clothing and equipment is provided, accessible and used;
(b)
Monitor employees’ exposure to the hazard;
(c)
Seek the consent of employees to monitor their health; and
(d)
With informed consent, monitor employees’ health.
To summarise important points in the motor industry, employers must
ensure that:
1
2
Every employee is adequately trained and/or supervised for every
particular job.
Unsafe practices are stopped immediately.
Health and Safety Guidelines for Tyre Fitters 62
3
All employees are supplied with suitable eye protection, overalls,
hearing protection, safety footwear and any other items necessary
to protect them from the hazards involved in their work.
4
Suitable tools and equipment are supplied for every particular job.
They must be of the correct type and in good condition. This
includes cage guards or other suitable restraining devices for tyre
inflation.
5
Manuals, wall charts, or other written instructions are available at
all times and cover the type of work being undertaken. Only methods set out and approved by the tyre/wheel manufacturers or
distributors are to be used.
Simply supplying these items is not enough. Employers must also ensure
that they are used or worn. Don’t allow anyone who either works for you, or
who is on your premises, to take chances with safety.
Public Access to Tyre Change Areas
Workplace or workshop areas where tyre changing is carried out should be
recognised by a sign warning: This is a hazardous area.
If practicable, a waiting room where customers can stay away from the tyre
changing area should be provided.
When public access is unavoidable, tyre change workshop areas where car
tyres are fitted should be separate from areas where heavy vehicle tyres are
fitted.
Clearly identify area where injury may occur. For example, use yellow
painted lines on the workshop floor marking areas to stay clear of.
These areas where tyre changing and inflation occurs should be kept clean
and clear of all tools and debris that could possibly become hazardous and
cause injury.
Working on Sites as a Contractor
The staff member working within a work site should be inducted into the
site through the system used on that site to inform of specific hazards that
may be present and the means of dealing with these hazards. They should
also be aware of all emergency procedures and any other appropriate information for working on that site.
Areas which should be employee only should have signage: No access unless
under the direct supervision of staff.
Health and Safety Guidelines for Tyre Fitters 63
19: The Employee’s
Responsibilities
Under the Health and Safety in Employment Act 1992, employees must
take all practicable steps to ensure their safety at work, and that no action
or inaction causes harm to any other person. Employees are also required to
use the protective clothing and equipment supplied for the job. Everyone
who installs or repairs tyres should follow these guidelines:
By law, employees
must take all
practicable steps to
ensure their safety at
work.
1
Don’t attempt any job unless you already know how to do it correctly and safely. Don’t bluff, or you may cause an accident. Ask
your supervisor for instructions — that’s what he or she is there
for.
2
Use only the correct tools, clothing and equipment for the job. If
gear is damaged, don’t use it. If in doubt, see your supervisor and
ask him or her to examine it, and to replace them if necessary.
3
4
Safety laws oblige you to observe safe work methods. If you are
unsure, stop and ask.
5
If you see anyone else not wearing or using safety clothing or
equipment, remind them to do so. You could save their eyesight or
their life.
Never take chances or let anyone else take chances with safety. In
particular, always wear your eye protection and always use tyre
cage guards or other suitable restraining devices when inflating
tyres removed from vehicles for any reason.
Health and Safety Guidelines for Tyre Fitters 64
20: Employee
Training Schedule
Every employer has an obligation to ensure that employees are adequately
trained in the safe use of all plant, objects, substances and protective clothing and equipment they are required to use. If they have not been trained, a
person with the requisite knowledge and experience must supervise them.
This is particularly important in the tyre industry, where many injuries are
serious.
Employers are
recommended to
complete and maintain
a training schedule for
each worker.
It is recommended that employers complete and maintain a training schedule for each worker. The training schedule can be used to prepare a list
showing each worker’s level of competence in specific tasks. This list should
be made available to both supervisors and workers and be posted in a
prominent position in the workplace so that those seeking assistance are
directed to a suitably trained person. The chart below is one way of expressing this information, although the format and information shown is likely to
vary from one business to another. The list of skills shown is, of course,
incomplete.
Phil
Tim
Bob Jules
Ted
Puncture repair
x
x
x
x
x
Car tyres
x
x
x
x
x
Use of jacks
x
x
x
x
x
Off-vehicle balancing
x
x
x
x
On-vehicle balancing
x
x
x
x
Divided rims
x
x
x
x
x
Tubeless truck tyres
x
x
x
Wide-base rims
x
x
x
H.T. licence
x
x
x
Outside repair unit
x
Compressor maintenance
x
x
Wheel alignment
x
x
x
x
Tyre companies, some polytechnics, and the Motor Industry Training Organisation have training courses and training resources, including books and
videos. In the first instance, you should ask your tyre suppliers for training
aids.
Health and Safety Guidelines for Tyre Fitters 65
21: Where to Get
Advice
I
f you have any doubts or questions about safety, ask your supervisor first.
If this is not possible, or the matter is not properly dealt with, you should
approach either your firm’s safety officer or your union delegate. If there is
no safety officer or union delegate and you are still not satisfied that the job
is safe, then contact a factory inspector at your nearest Occupational Safety
and Health Service (OSH) office. Employers who have any questions concerning safety or safety legislation should also contact their nearest OSH
office.
Technical matters should be referred to the organisations whose contact
details are given in this book.
Any enquiries regarding standards should be referred to the Standards
Association of New Zealand.
Land Transport Rule: Tyres and Wheels
Land Transport Rule: Tyres and Wheels is proposed transport legislation at
this time (March 2001). If passed, it will replace existing land transport
legislation for tyres and wheels. The new legislation is intended to ensure
that all vehicles have tyres and wheels that meet an acceptable level of
safety when fitted, and throughout their on-road life. The rule is applicable
to all vehicles used on the road at any time, and covers modifications and
repairs.
Tyre Safety Issue Boundary Between OSH and LTSA
The LTSA has responsibility for vehicle safety on public roads. This responsibility includes the vehicle tyres, and where a spare wheel is carried by a
vehicle, the safety aspects of spare wheel security.
OSH has responsibility for safety in the manufacture, fitting, repair, and
storage of tyres in places of work.
Web Sites (NZ)
Land Transport Safety Authority
http://www.ltsa.govt.nz/homepage.shtml
Occupational Safety and Health Service of the Department of Labour, New
Zealand
http://www.osh.dol.govt.nz
Health and Safety Guidelines for Tyre Fitters 66
References
Books and Standards
Vehicle Standards: What makes car safety tick, Land Transport Safety Authority; pp 19-21, Tyres
Compressed air safety, HSE Books, 2nd edition, 1998
Guidance on the handling, storage and transport of airbags and seat belt
pretensioners, HSE Books, 1998
A guide to the handling and storage of airbags and seat belt pretensioners at
garages and motor vehicle repair workshops, HSE Books, 1998
Tyres, wheels and rim assemblies: Safe removal, assembly and inflation,
Tasmania Department of Labour and Industry, 1986
Assembling truck and tractor tyres and rims, WorkCover Authority of New
South Wales, (leaflet, illus.), 1991
AS/NZS 1268:1996 Equipment for checking pressure and inflation of tyres.
(Specifies minimum requirements for tyre pressure gauging equipment when
used to measure, inflate, control or adjust the pressure of tyres used on
road vehicles.)
Joint Australian/New Zealand Standards
NZS 5423:1996 Specification for repairing and retreading car, truck and bus
tyres Amend: 1 1998
(Specifies the minimum requirements for the repairing and retreading of
car, truck and bus pneumatic tyres used in highway service. It specifies
certain constructional features such as the examination, limits of damage,
preparations and permissible repairs of the tyre carcass before processing,
and the marking and inspection of the tyre after curing. Minimum performance levels are also given. Except where otherwise stated, the requirements
apply to both tubed and tubeless tyres.)
Cited in Import Control (Tyres) Conditional Prohibition Order 1996
NZS 5453:1989 New tyres for passenger vehicles
(Specifies requirements of strength, construction and standard pressure/
load relationships for new pneumatic tyres for passenger cars and prescribes
tests required for their acceptance.)
Cited in Transport (Vehicle Standards) Regulations 1990, Import Control
(Tyres) Conditional Prohibition Order 1996
NZS 5464: 1990 Pneumatic tyres - Light truck and truck/bus - New (=AS
2230-1990)
(Specifies requirements for physical dimensions, performance, and marking
for new pneumatic light truck, and truck/bus tyres designed primarily for
on-road use.)
Health and Safety Guidelines for Tyre Fitters 67
Cited in Transport (Vehicle Standards) Regulations 1990; Import Control
(Tyres) Conditional Prohibition Order 1996
Other Tyre-Related Web Sites
Beaurepaires
http://www.beaurepaires.co.nz
Bridgestone — Answers to some of the most common questions about tyres
http://www.bridgestone-tyres.com/faq.htm
Dunlop Tyres Ltd.
http://www.dunloptyres.co.uk/00home.html
National Highway Traffic Safety Administration (U.S.A.)
http://www.nhtsa.dot.gov
National Tyre Distributors Association, United Kingdom
http://www.ntda.co.uk/safety.htm
OSHA Regulations (Standards - 29 CFR)
Servicing multi-piece and single-piece rim wheels. - 1910.177
http://www.osha-slc.gov/OshStd_data/1910_0177.html
SafetyLine, an on-line information service provided by WorkSafe Western
Australia
http://sage.wt.com.au/safetyline
Tyre Safety Australia
http://www.worksafe.gov.au
Health and Safety Guidelines for Tyre Fitters 68
Appendix 1: Wheel
Restraint Device
Example of a portable restraint device
which packs in a compact space for
convenient transport to field work.
Health and Safety Guidelines for Tyre Fitters 69
Appendix 2: Tyre
Construction
Three types of tyre constructions are common in New Zealand, namely
crossply (bias ply), textile radial, and steel radial construction.
The following diagrams illustrate the basis of these constructions.
Crossply (or Bias Py) Construction.
This construction has the ply cords extend to the beads and laid
at opposing angles of approximately 400 to the tread centreline.
The carcass is normally of either nylon or polyester construction.
Textile Radial Construction
The textile radial ply tyre has its body plies laid at an angle of
approximately 900 to the tread centreline. The casing material is
usually of textile cords, as are the breaker plies or belts which
sit centrally on the crown of the tyre below the tread. The body
plies which run radially from bead to bead (giving the tyre its
name) provide very flexible sidewalls compared to the crossply
tyre, but the tread area is reinforced to a heavier degree, providing improved mileage over the traditional crossply tyre.
Steel-Belted Radial Construction
Similar in construction to the textile radial tyre, the fundamental difference is the replacement of the multiple textile belts
with two belts of high-tensile steel. These tough steel belts
which encircle the casing provide an inextensible foundation for
the tread to sit on, providing superior cornering and high speed
handling dynamics, together with longer tyre life.
Health and Safety Guidelines for Tyre Fitters 70
Appendix 3: Glossary
of Terms
Approved Rim Widths Codes
The only allowable rim widths for a
specific size of tyre.
Aspect Ratio
This is the ratio between the tyre section
width and the height of the sidewall.
Early tyre designs had an aspect ratio of
100%, which means that the section
height and width are equal.
With modern cars capable of much higher speeds, the tyre manufacturers
have now designed tyres with decreased aspect ratios to complement the
increased performance of vehicles. Today’s modern sports cars are now
fitted with 50%, 45%, 40%, or even 35% aspect ratios.
Asymmetric Patterns
An asymmetric tread pattern generally consists of dissimilar tread pattern
elements placed radially opposite each other in order to optimise pattern
characteristics.
Bead
That part of a pneumatic tyre which fits and holds the tyre securely onto
the wheel rim. It consists of a coil of high-tensile steel wire, treated to give
good adhesion with rubber, and encased in a “matrix” of hard rubber.
Health and Safety Guidelines for Tyre Fitters 71
Breaker
A strip of rubber-coated cord fabric, or steel cord, fitted between the tread
and casing of a radial ply tyre, running on a bias circumferentially around
the tyre.
Cap and Base
A pneumatic tyre tread formed from two separate strips of compound each
having different physical characteristics; the upper strip or cap forming the
tread pattern and the lower strip of base forming the undertread.
Chafer
A strip of rubberised cross-woven fabric fitted around the part of the tyre
bead which comes into contact with the rim.
Clinch
The area of the sidewall of a pneumatic tyre immediately above the rim
flange where severe stress occurs in service.
Compound
Natural or synthetic rubber, or a blend of both, treated with various chemicals and other materials to give specific properties required for various
commercial rubber products.
Deflection
The degree to which the section of an inflated tyre distorts or deflects
under load. The ratio of the loaded section height to the unloaded section
height of a tyre, expressed as a percentage.
Directional Tread
A tread formed with “Chevron” grooves used on tyres providing good traction combined with self cleaning properties. Tyres with directional treads
must be fitted with the point of the chevron pointing in the direction of
travel, otherwise traction will be lost.
D.O.T.
Department of Transportation (USA) tyre safety standards. The letters
appear on the sidewall of passenger tyres manufactured in America or for
the American market.
Flap
A circular strip of rubber or fabric-reinforced rubber used in pneumatic
Health and Safety Guidelines for Tyre Fitters 72
tyres to prevent chafing of the inner tube on the rim. Quite commonly
known in New Zealand as a “Rustband”.
Footprint
The ground contact area of a tyre tread.
Inner Liner
The air retaining part of a tubeless tyre. It is an integral part of the tyre
and consists of a sheet of special rubber compound fitted to the underside
of the first (inside) casing ply.
Load Index
A numerical system of marking tyres to indicate their load-carrying limits.
The load index is related to ply rating.
Load range
The term “Load Range”, and its designating letter, is used to identify a
given tyre size with its load and inflation limits when used for a specific
type of service, as defined in the TRA tables. Load ranges are normally
only used on tyres of USA or Canadian manufacture. (A = 2PR, B = 4PR,
C = 6PR etc.)
Loaded Section Width
The width of the cross section of a tyre under load.
Low Profile Tyres
Any tyre having a section height to section width ratio (aspect ratio) of 80%
or lower.
Maximum Inflation Pressure
Maximum cold pressure required to carry the maximum load.
Maximum Load
Maximum carrying capacity of the tyre when run at maximum inflation
pressure, at a given speed.
Millimetre Tyres
Tyres marked with the section width in millimetres, and the rim diameter in
inches, e.g. 165 R 13.
Health and Safety Guidelines for Tyre Fitters 73
Minimum Dual Spacing
The minimum recommended distance between centrelines of dual-mounted
tyres to avoid touching or chafing in the flex area.
Non-directional Tread
A general-purpose tread pattern designed so that the tyre can be run in
either direction without loss of traction or self-cleaning properties.
Overall Diameter (od)
The diameter of an unloaded tyre, mounted on its recommended rim and
inflated to service pressure.
Plies
Sheets of rubber-coated textile or steel wire cords from which the casing of
a tyre is constructed. A single ply consists of a sheet of cord fabric or steel
in which the cords run parallel to one another and are insulated from each
other by a layer of resilient rubber compound.
Ply Rating
The term “ply rating” is now used to identify a given tyre with its maximum
recommended load for its specific job. It is an index of tyre strength and
does not necessarily represent the number of actual plies. The ply rating
system is being discontinued in favour of load indices.
Rim Width
The section of a wheel on which the beads of a pneumatic tyre are fitted.
Rim Fitting Line
A narrow rib, part of the sidewall rubber running circumferentially around a
tyre just above the bead, used as a guide line to check that a tyre when
fitted to its wheel is correctly seated on the rim.
Rim Flange
The shoulders of the rim of a wheel which fit against the face of the bead
and which hold the tyre on the rim.
Section Height (SH)
The distance from the bead seat to the outer tread contour of the inflated
tyre — at the centreline.
Health and Safety Guidelines for Tyre Fitters 74
Section Width (SW)
The width of the inflated tyre section, excluding any lettering or decoration.
Static Loaded Radius (SLR)
The standing height from the road surface to the axle centre under nominal
load/inflation conditions.
Tread
The wearing surface of the tyre, i.e. that part of the tyre which makes
contact with the road.
Tread Wear Indicators
Various devices incorporated in the base of the tread pattern of a tyre,
usually in the form of small raised platforms spaced at intervals around the
base of the circumferential grooves of the pattern.
Tube
The tube or “inner tube” is part of a tyre assembly and holds the air under
pressure.
Wheel Offset
Distance from the rim centreline to the inner (hub contact) face of the
wheel disk, measured in millimetres. A wheel with a positive offset will have
the centreline inboard of the contact face, whereas a wheel with negative
offset will have the wheel centreline outboard of the contact face.
Health and Safety Guidelines for Tyre Fitters 75