Transportation Training
Wheel Alignment
Why Align the Wheels?
Correct Wheel alignment is essential to vehicle safety.
Improve Handling Ability
Maximum Fuel Economy
Prolong Tire Life
By Allowing the tires to
roll freely without
scuffing or slipping
sideways under any
operating conditions
Alignment Angles and
Adjustments
1.
Caster
2. Camber
3. Toe-in/out
Non adjustable
4.Ride height
7.Scrub Radius
5.Thrust Angle or Tracking
8.Steering Axis
Inclination
6.Steering Center
9.Toe-Out on Turns
Caster
Positive for power steering
Negative for manual steering
Caster is the
forward or
rearward tilt of
the Steering
Knuckle
Caster is adjustable
To increase Directional Control of
the vehicle
When viewed from
To compensate for Road Crown
the side of the
Pull.
vehicle.Measured
To help the wheels to return to
in degrees.
the straight-ahead position.
Camber
Common camber settings
are ¼ to ½ degree positive
Camber is the
inward or outward
tilt of the top of
the wheel and tire
assembly
Camber is adjustable
To prevent tire wear on the
outer or inner tread
When viewed from
the front of the
vehicle. Measured
in degrees.
To load the larger inner wheel
bearing vs. the smaller
outer bearing.(Positive)
To aid steering by placing the
weight on the inner end of the
spindle and reducing scrub radius.
Toe-in /Toe-out
Common Settings:
Front Wheel Drive 1/16” or 1.5 mm
Rear W Drive 1/16” to ¼” or 1.6 to 6 mm
Toe-in
Is the inward or
outward direction
of both left and
right wheel and
tire assemblies
is when the front tires are
closer at the front than at the rear
When viewed from
above the vehicle.
Measured in inches
or millimeters or
degrees.
Ride Height
Measured in inches or
centimeters at 4
locations close to each
wheel
Ride height is
measured from the
rocker panel to the
ground surface
Thrust Angle or Tracking
Thrust angle is the
direction that the
rear wheels are
pointing in relation to
the center line of
the vehicle.
Thrust angle
should be zero and
is only adjustable
on certain
vehicles.
Steering Wheel Center
Steering center is simply the
fact that the steering wheel
is centered “level” when the
vehicle is traveling down a
straight and level road.
Adjusted by toe
settings and affected
by thrust angle.
Common Adjustments
The most common
adjustments are Caster,
Camber, Toe, and Thrust
angle
Pre Alignment Inspection
Worn Tires
Tire Pressure
Tire Size and Type
Wheel or Tire runout
Cradle Alignment
Loose Wheel Bearings
Ride Height and Weight
Worn Steering and
Suspension Components
Tech Tip: Always Road test
the vehicle before doing a
wheel alignment. This helps
to detect problems, like
pulling or worn components.
Reading Tire Wear
Abnormal Tire Wear is Caused by
Incorrect Tire Pressure
Excessive Camber
Incorrect Toe Settings
Lack of Rotation
Unbalanced Tire
Under Rated Tires
Driving Conditions
Making Adjustments
Caster is adjusted by moving the
control arm so that the ball joint moves
toward the front or rear of the vehicle
and is not always adjustable.
Making Adjustments
Camber is changed by moving the
control arm in or out without moving
the ball joint forward or rearward..
Making Adjustments
Toe angle is adjusted by lengthening or
shortening the tie-rods..
.
Suspension Types
Mac Pherson Strut
Suspension with
Rack and Pinion
Steering
Conventional Suspension &
Parallelogram Steering
ASE-Type Questions
Automotive
Service
Excellence
Chapter 74
Transportation Training
Wheel Alignment
The End