miles to warm tires (remove any flat spots). Lightly
place hands on steering wheel at the 10:00 and 2:00
positions while slowly sweeping up and down from 90
to 110 km/h (55 to 70 mph) where legal speed limits
allow.

Observe the steering wheel for:
• Visual Nibble (oscillation: clockwise/counter-

clockwise, usually due to tire imbalance)

TIRES/WHEELS

22 - 1

• Visual Buzziness (high frequency, rapid vibra-

tion up and down)

To rule out vibrations due to brakes or powertrain:
• Lightly apply brakes at speed; if vibration occurs

or is enhanced, vibration is likely due to causes other
than tire and wheel assemblies.

• Shift transmission into neutral while vibration

is occurring; if vibration is eliminated, vibration is
likely due to causes other than tire and wheel assem-
blies.

For brake vibrations, (Refer to 5 - BRAKES -

BASE/HYDRAULIC/MECHANICAL/ROTORS

DIAGNOSIS AND TESTING).

For powertrain vibrations, (Refer to 3 - DIFFER-

ENTIAL & DRIVELINE - DIAGNOSIS AND TEST-
ING).

For tire and wheel assembly vibrations, continue

with this diagnosis and testing procedure.

TIRE AND WHEEL BALANCE

(1) Balance the tire and wheel assemblies as nec-

essary following the wheel balancer manufacturer’s
instructions and using the information listed in Stan-
dard Procedure - Tire And Wheel Balance. (Refer to
22 - TIRES/WHEELS - STANDARD PROCEDURE)

(2) Road test the vehicle for at least 5 miles, fol-

lowing the format described in Road Test.

(3) If the vibration persists, continue with this

diagnosis and testing procedure.

TIRE AND WHEEL RUNOUT/MATCH MOUNTING

(1) System Radial Runout. This on-the-vehicle

system check will measure the radial runout includ-
ing the hub, wheel and tire.

(a) Raise vehicle so tires clear floor. (Refer to

LUBRICATION & MAINTENANCE/HOISTING -
STANDARD PROCEDURE)

(b) Apply masking tape around the circumfer-

ence of the tire in the locations to be measured
(Fig. 2). Do not overlap the tape.

Set, Special Tool C-3339A with 25-W wheel, or
equivalent. Place the end of the indicator against
each taped area (one at a time) (Fig. 2) and rotate
the tire and wheel. System radial runout should
not exceed 0.76 mm (0.030 inch) with no tread
“dips” or “steps.” Tread “dips” and “steps” can be
identified by spikes of the dial indicator gauge.
• Tread 9dips9; Rapid decrease then increase in

dial indicator reading over 101.6 mm (4.0 inch) of
tread circumference.

• Tread 9steps9; Rapid decrease or increase in dial

indicator reading over 101.6 mm (4.0 inch) of tread
circumference.

(d) If system runout is excessive, re-index the

tire and wheel assembly on the hub. Remove
assembly from vehicle and install it back on the
hub two studs over from original mounting posi-
tion. If re-indexing the tire and wheel assembly
corrects or reduces system runout, check hub
runout and repair as necessary (Refer to 5 -
BRAKES

BASE/HYDRAULIC/MECHANICAL/

ROTORS - DIAGNOSIS AND TESTING).

(e) If system runout is still excessive, continue

with this diagnosis and testing procedure.

Fig. 1 Aluminum Wheel Weight

1 - TIRE
2 - WHEEL
3 - WHEEL WEIGHT

Fig. 2 Radial Runout Measurement

1 - MASKING TAPE
2 - DIAL INDICATOR

22 - 2

TIRES/WHEELS

TIRES/WHEELS (Continued)

(2) Tire and Wheel Assembly Radial Runout.

This radial runout check is performed with the tire
and wheel assembly off the vehicle.

(a) Remove tire and wheel assembly from vehicle

and install it on a suitable wheel balancer.

(b) Check system runout using Dial Indicator

Set, Special Tool C-3339A with 25-W wheel, or
equivalent. Place the end of the indicator against
each taped area (one at a time) (Fig. 2) and rotate
the tire and wheel. Radial runout should not
exceed 0.76 mm (0.030 inch) with no tread “dips”
or “steps.” Tread “dips” and “steps” can be identi-
fied by spikes of the dial indicator gauge.

location of the tire on the wheel at the valve stem
(Fig. 3). Also, mark the tire and wheel to indicate
the original high spot of the assembly and record
the runout measurement.

(d) If runout exceeds limits, the tire will need to

be dismounted from the wheel to verify wheel vs.
tire contribution. Refer to Wheel Runout below.

(3) Lateral Runout. Lateral runout for the vehi-

cle system as well as the tire and wheel assembly
should be less than 0.76 mm (0.030 inch). The same
procedure and theory described for radial runout can
also be applied to identify and reduce lateral runout.

(4) Wheel Runout. This runout check is per-

formed as follows:

(a) Dismount the tire from the wheel.
(b) Mount the wheel back on the wheel balancer.

tire bead seat (Fig. 4). Runout should not exceed
0.36 mm (0.014 inch) for aluminum wheels and
0.80 mm (0.031 inch) for steel wheels. Replace the
wheel if it exceeds the limit.

(d) Measure lateral runout of the wheel at the

tire bead seat (Fig. 5). Runout should not exceed
0.762 mm (0.030 inch) for all wheels. Replace the
wheel if it exceeds the limit.

Fig. 3 Marking Tire

1 - REFERENCE MARK
2 - EXAMPLE HIGH SPOT ON TIRE
3 - WHEEL
4 - VALVE STEM

Fig. 4 Checking Radial Runout Of Wheel

1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR

Fig. 5 Checking Lateral Runout Of Wheel

1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR

TIRES/WHEELS

22 - 3

TIRES/WHEELS (Continued)

(5) Match Mounting. If the wheel runout is

within specifications, tire and wheel assembly runout
can be improved by re-indexing (match mounting)
the tire to the wheel as described below.

(a) Remount the tire on the rim 180 degrees

from its original location (Fig. 6). Ensure the tire
bead is properly seated.

(b) Re-measure the total runout. Mark the tire

at the high spot and record the measurement.

If runout is still excessive, perform the following:
• If the new high spot is within 102 mm (4.0 inch)

of the first high spot on the tire, replace the tire.

• If the new high spot is within 102 mm (4.0 inch)

of the first high spot on the wheel, the wheel may be
out of specification. Refer to Wheel Runout above.

• If the new high spot is NOT within 102 mm (4.0

inch) of either high spot, draw an arrow on the tread
from new high spot toward the original (Fig. 7).
Break down the tire and remount it 90 degrees on
rim in that direction, then re-measure runout. This
will normally reduce the runout to an acceptable
amount.

(6) Once back together, road test the vehicle for at

least 5 miles, following the format described in Road
Test. If vibration persists, and all components tested
are within specification, the tires may have an exces-
sive radial force condition. Radial force variation can
only be checked as indicated below. If this equipment
is not available, consult with the tire manufacturer.

RADIAL FORCE VARIATION

Radial Force Variation can be checked using the

Hunter GSP 9700 Vibration Control System (Wheel
Balancer) or equivalent, if available. This type of
equipment helps to correct ride disturbances by
reducing the radial force variation of an assembly
through re-indexing of the tire to wheel.

The equipment manufacturer or DaimlerChrysler

Corporation may supply reference values as guide-
lines. Radial force measurements above the reference
value may not always result in a ride disturbance,
nor do they automatically mean the assembly compo-
nents are out of specification. Do not replace compo-
nents based on radial force values alone. Balancing,
runout diagnosis, re-indexing, and subjective road
testing must be performed as outlined in previous
sections of this diagnosis and testing procedure.

Use the Radial Force equipment to identify suspect

assemblies and minimize the radial forces. After all
suspect

assemblies

are

optimized,

reinstall

the

assemblies and road test the vehicle. If a disturbance
still exists and all other vibration diagnostic proce-
dures have been completed, replace one tire or one
wheel at a time, starting with the assembly having
the highest force variation. Be sure to minimize each
new assembly. Road test the vehicle following each
replacement. Continue this process until the distur-
bance is resolved.

Fig. 6 Remount Tire 180 Degrees

1 - VALVE STEM
2 - REFERENCE MARK

Fig. 7 Remount Tire 90 Degrees In Direction of

Arrow

1 - 2ND HIGH SPOT ON TIRE
2 - 1ST HIGH SPOT ON TIRE

22 - 4

TIRES/WHEELS

TIRES/WHEELS (Continued)

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