Jeep 1997 Grand Cherokee Service Manual page 2130

SURE TO SPEC- ARE WHEN IFICATIONS ADJUST ROTATE TIRES CONDITION EFFECT CAUSE PRES- TIRES COOL RAPID SHOULDERS RAPID WEAR
UNDER-INFLATION
OR LACK OF ROTA-
TION
22 - 4 TIRES AND WHEELS
DIAGNOSIS AND TESTING (Continued)
TIRE NOISE OR VIBRATION
Radial-ply tires are sensitive to force impulses
caused by improper mounting, vibration, wheel
defects, or possibly tire imbalance.
To find out if tires are causing the noise or vibra-
tion, drive the vehicle over a smooth road at varying
speeds. Note the effect of acceleration and decelera-
tion on noise level. Differential and exhaust noises
will change in intensity as speed varies, while tire
noise will usually remain constant.
SERVICE PROCEDURES
ROTATION
Tires on the front and rear axles operate at differ-
ent loads and perform different steering, driving, and
braking functions. For these reasons;
• They wear at unequal rates
• Tend to develop irregular wear patterns
These effects can be reduced by timely rotation of
tires. The benefits of rotation are especially worth-
while. Rotation will:
• Increase tread life
• Help to maintain mud, snow, and wet traction
levels
• Contribute to a smooth, quiet ride
The suggested method of tire rotation is (Fig. 6).
Other rotation methods can be used, but they will
not provide all the tire longevity benefits.
MATCH MOUNTING
NOTE: Tires and wheels
mounted at the factory.
AT ADJUST CAMBER TO SPECIFICATIONS WEAR CENTER AT OR UNDER-INFLATION CRACKED TREADS WEAR ON ONE SIDE EXCESSIVE
OVER-INFLATION
OR LACK OF ROTA-
TION
Fig. 5 Tire Wear Patterns
are currently
SPEED* ADJUST TOE-IN TO SPECIFICATIONS DYNAMIC FRONT STATIC FEATHERED EDGE
EXCESSIVE CAMBER
Match mounting is a technique used to reduce
runout in the wheel/tire assembly. This means that
the high spot of the tire is aligned with the low spot
on the wheel rim. The high spot on the tire is
marked with a paint mark or a bright colored adhe-
sive label on the outboard sidewall. The low spot on
the rim is identified with a label on the outside of the
rim and a dot on the inside of the rim. If the outside
label has been removed the tire will have to be
removed to locate the dot on the inside of the rim.
Before dismounting a tire from its wheel, a refer-
ence mark should be placed on the tire at the valve
stem location. This reference will ensure that it is
remounted in the original position on the wheel.
(1) Measure the total indicator runout on the cen-
ter of the tire tread rib. Record the indicator reading.
match
Mark the tire to indicate the high spot. Place a mark
on the tire at the valve stem location (Fig. 7).
BALANCE WHEELS OR AND ROTATE SUSPENSION SEE BALD SPOTS GROUP 2 INSPECT TIRES
INCORRECT TOE LACK OF ROTATION OF TIRES OR UNBALANCED WHEEL
WORN OR OUT-OF-ALIGNMENT
OR TIRE DEFECT*
SUSPENSION.
Fig. 6 Tire Rotation Pattern
SCALLOPED WEAR CORRECTION
*HAVE TIRE INSPECTED FOR
FURTHER USE.
ZG