SERVICE PROCEDURES
TIRE AND WHEEL ROTATION (NON-DIRECTIONAL
THREAD PATTERN)
Tires on the front and rear axles operate at differ-
ent loads and perform different functions. For these
reasons, they wear at unequal rates, and tend to
develop irregular wear patterns. These effects can be
reduced by timely rotation of tires. The benefits of
rotation are especially worthwhile. Rotation will
increase tread life, help to maintain mud, snow, and
wet traction levels, and contribute to a smooth, quiet
ride.
The suggested rotation method is the forward-cross
tire rotation method (Fig. 6). This method takes
advantage of current tire industry practice which
allows rotation of radial-ply tires. Other rotation
methods may be used, but may not have all the ben-
efits of the recommended method.
NOTE: Only the 4 tire rotation method may be used
if the vehicle is equipped with a low mileage or tem-
porary spare tire.
REPAIRING TIRE LEAKS
For proper repairing, a radial tire must be removed
from the wheel. Before dismounting the tire from the
wheel, a reference mark should be placed on the tire
at the valve stem location. This reference mark will
ensure that the tire is remounted back on the wheel
in its original position. Repairs should only be made
if the defect, or puncture, is in the tread area (Fig.
7). The tire should be replaced if the puncture is
located in the sidewall.Deflate tire completely before dismounting tire
from the wheel. Use lubrication such as a mild soap
solution when dismounting or mounting tire. Use
tools free of burrs or sharp edges which could dam-
age the tire or wheel rim.
Before mounting tire on wheel, make sure all rust
is removed from the rim bead and repaint if neces-
sary.
Install wheel on vehicle, and progressively tighten
all 5 wheel nuts to a torque of 135 N´m (100 ft. lbs.).
TIRE AND WHEEL MATCH MOUNTING
Wheels and tires are match mounted at the factory.
This means that the high spot of the tire is matched
to the low spot on the wheel rim. This technique is
used to reduce run-out in the wheel/tire assembly.
The high spot on the tire is marked with a paint
mark or a bright colored adhesive label on the out-
board sidewall. The low spot on the rim is identified
with a label on the outside of the rim and a dot or
line on the inside of the rim. If the outside label has
been removed the tire will have to be removed to
locate the dot or line 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.
Mark the tire to indicate the high spot. Place a mark
on the tire at the valve stem location (Fig. 8).
(2) Break down the tire and remount it 180
degrees on the rim (Fig. 9).
(3) Measure the total indicator runout again. Mark
the tire to indicate the high spot.
Fig. 6 Forward-Cross Tire Rotation Method
Fig. 7 Tire Repair Area
22 - 6 TIRES AND WHEELSNS
