1 second in time
1st cycle
2nd cycle
2 cycles per second or 2 Hz
1 second in time
1st cycle
2nd cycle
Frequency is 2 CPS or 2 Hz
Imbalance
1 second
4 Revolutions = Frequency of 4
CPS/Hz
If the Frequency increases...
Imbalance
1 second
6 Hz
Amplitude of Force
so does the amplitude of force
can identify Frequency
500
250
Hz
100
25
Static Balance is when the
weight of the wheel and
tire assembly is
distributed equally around
the axis of the wheel
rotation.
If static Balance exists the
wheel will have no
tendency to rotate.
If rotated it rotates with
Equal Force
Heavy Area Rotates to Bottom
.25 oz Imbalance
.25 oz imbalance
.25 oz weight added
.25 oz imbalance
.25 oz weight added
the
is the word
“Perfectly”
.25 ounces of imbalance generates
.86 pounds of force
.86 lbs
Imbalance in Tire
.86 lbs
Balance Weight Applied
.25 ounces of imbalance generates
10.5 pounds of force
10.5 lbs.
10.5 lbs.
It's still in perfect balance!
10.53 lbs.
NOTE: Speed rated Tires
Utilize a Nylon Over-lay to
prevent tire distortion at
high speeds.
10.53 lbs.
•Round Off vs. Fine Mode
•Mounting
•Clean Mounting Surface
•Excessive Runout
•Tolerance stack up
Most Computer Wheel Balancers
Round off to the nearest .25 oz.
1 oz. Balance Weight
1.12 oz. Imbalance
Is this a Problem?
.25 Round Off = .12 Error
1 oz. Balance Weight
1.12 oz. Imbalance
Is this a Problem?
this Slight Imbalance would not be
felt, however
RESONANCE
you must understand an objects
Natural Frequency
Mechanical Objects have there own
Natural Frequency
Imbalance
1 second
4 Revolutions = Frequency of 4
CPS/HZ
Amplitude of Force
Imbalance
1 second
6 Hz
Range from 10 - 15 Hz/CPS
14 Hz
12 Hz
Suspension Frequency
Tire & Wheel Frequency
1st order harmonic
15
10
5
0
10
20
30 40
50
60
can it be balanced to Zero?
Yes, balance only refers to force
can be off-center as
much as .010”
Duplicate O.E.M. Mounting
Are wheels centered by the center hole?
Hub-centric
Are wheels centered by the lug nuts?
Lug-centric
95% of O.E.M wheels are Hub-centric
&
*100% through 1 Ton
*(as of 1/1/00)
Corvette Wheel
Hub-centric
Tire High Spot
Wheel
High
Spot
Max assembly radial and lateral runout is
.050” measured off the vehicle and
.060” on the vehicle
Note: Rule of thumb for passenger cars and light trucks
Radial Runout
1st order harmonics
15
10
5
0
10
20
30 40
50
60
Mis-Matched
Matched
Lateral Runout
.045” Steel Wheel*
.030” Aluminum*
Radial Runout
.040” Steel Wheel*
.030” Aluminum*
* Reference GM
Measure runout at bead seat area
Radial Runout
.040” Steel Wheel*
.030” Aluminum*
* Reference GM
Measure lateral runout at inside rim lip
Lateral Runout
.045” Steel Wheel*
.030” Aluminum*
* Reference GM
Lateral Runout
.050” Off Vehicle*
.060” On Vehicle*
Radial Runout
.050” Off Vehicle*
.060” On Vehicle*
* Reference GM
Tape
Radial Runout
.050” Off Vehicle*
.060” On Vehicle*
* Reference GM
Lateral Runout
.050” Off Vehicle*
.060” On Vehicle*
* Reference GM
1 oz. Imbalance
Is normally not a problem
under 30MPH
Under 30MPH Excessive
Lateral Runout of Tire/Wheel
can cause
Low Speed “Waddle”
Bulges indicate
weak areas and
indention's are
strong areas
“Radial Force Variations”
“Radial Force Variations”
Manufacturers Test for Radial
Force Variations at the Factory
…and it is not a common problem
.011” Can Results
in 1oz. Dynamic
Imbalance Error
.011” Can Results
in 1oz. Dynamic
Imbalance Error
Duplicate O.E.M. Mounting
Back Cone
-orFront Cone
Hub Centric
-orLug Centric
Check Cones for Damage or Wear
2.000”
2.001”
On a 36 lb. Tire and Wheel, .006” cone
wear can result in 1/2 ounce imbalance
2.000”
2.006”
Off center .006”
creates more mass on
one side