21
MEASURING CAMBER, CASTER, AND SAI
Measuring Caster, Camber or SAI is very simple and fast.
Before performing these measurements:
x
The equipment must be calibrated.
x
The wheel clamps must be mounted and adjusted for run out.
x
The full weight of the vehicle must be on its wheels
x
It is recommended to use turntables and slip plates when measuring caster, camber and
SAI.
x
The vehicle should be jounced to settle the suspension
Measuring Camber:
Camber readings are taken on all the wheels with the TR-30 Easy Check Gauge. You may measure
front camber as well by using the bubble scale on each of the Combi Gauges provided that the
camber does not exceed plus or minus three degrees. (Note that rear camber only needs to be
adjusted when performing a four-wheel alignment.)
1)
Hang the TR-30 on the left front wheel clamp to measure camber, caster and SAI.
2)
With the wheels in a straight-ahead position, note the reading of the camber bubble on the
TR-30 and compare with factory specifications.
3)
Repeat process on the right front wheel clamp.
4)
To measure front camber, use the TR-38 and TR-39 Combi gauges, which have a camber
scale on each. If the vehicle has a front camber greater than +-3 degrees, use the TR-30 to
take the reading.
Note:
Any and all adjustments to caster or camber must be made before measuring toe.
Measuring Caster:
Caster readings are taken on the front wheels, using the TR-30.
1)
Hang the TR-30 on the left front wheel clamp to measure camber, caster and SAI.
2)
Install brake pedal depressor and lock brakes so they do not rotate. With power brakes start
the engine to install brake pedal depressor. This is optional; this is only done to prevent the
vehicle from rolling during measurement.
3)
Release the pin on the turntable. This allows the wheel to pivot, or turn, freely.
4)
From a straight-ahead position, turn the wheel
out
20 degrees. (Use the scale on the
turntable to confirm swing.)
5)
Level the TR-30, using the SAI scale on the top of the TR-30; adjust the caster bubble to
zero, using the knob on the body of the TR-30.
6)
Turn the wheel
in
a total of 40 degrees, or until the wheel is 20 degrees
in
on
the scale of the turntable.
7)
Read the number corresponding to the bubble on the caster scale.
8)
Repeat this process on the right front wheel.
Note:
Any and all adjustments to caster, camber or SAI, if required, must be made before
measuring toe.
12
11
10
9
8
7
6
5
4
3
2
1
0
1
2
3
4
5
6
+
R
E
T
S
A
C
-
6
5
4
3
6
5
4
3
3
2
1
0
1
2
3
+
C
A
M
B
E
R
-
