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22 - 4
TIRES/WHEELS
TIRES/WHEELS (Continued)
(b) Re-measure the total runout. Mark the tire
at the high spot and record the measurement.
Fig. 6 Remount Tire 180 Degrees
1 - VALVE STEM
2 - REFERENCE MARK
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.
Fig. 7 Remount Tire 90 Degrees In Direction of
1 - 2ND HIGH SPOT ON TIRE
2 - 1ST HIGH SPOT ON TIRE
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.
NOTE: When using Radial Force equipment, it is
critically important to set proper tire inflation pres-
sure and ensure centering of the wheel on the
equipment spindle.
Arrow
JR
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