
TIRES / WHEELS
TABLE OF CONTENTS
page page
TIRES/WHEELS
DIAGNOSIS AND TESTING - TIRE AND
WHEEL RUNOUT......................1
STANDARD PROCEDURE
STANDARD PROCEDURE - MATCH
MOUNTING...........................2
STANDARD PROCEDURE - TIRE AND
WHEEL BALANCE......................4
STANDARD PROCEDURE - TIRE ROTATION . 6
SPECIFICATIONS
TORQUE CHART......................7
TIRES
DESCRIPTION
DESCRIPTION - TIRES..................7
DESCRIPTION - RADIAL ± PLY TIRES......7
DESCRIPTION - TIRE PRESSURE FOR
HIGH SPEEDS.........................8
DESCRIPTION - REPLACEMENT TIRES.....8
DESCRIPTION - TIRE INFLATION
PRESSURES..........................8
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - PRESSURE
GAUGES.............................9
DIAGNOSIS AND TESTING - TIRE NOISE
OR VIBRATION........................9
DIAGNOSIS AND TESTING - TREAD WEAR
INDICATORS..........................9DIAGNOSIS AND TESTING - TIRE WEAR
PATTERNS...........................9
DIAGNOSIS AND TESTING - TIRE/VEHICLE
LEAD...............................10
STANDARD PROCEDURE - REPAIRING
LEAKS..............................12
CLEANING............................12
SPECIFICATIONS
TIRES..............................12
SPARE TIRE CARRIER
REMOVAL.............................12
INSTALLATION.........................12
WHEELS
DESCRIPTION.........................13
OPERATION...........................13
DIAGNOSIS AND TESTING
WHEEL INSPECTION..................13
STANDARD PROCEDURE
STANDARD PROCEDURE - WHEEL
REPLACEMENT.......................13
STANDARD PROCEDURE - DUAL REAR
WHEEL INSTALLATION.................13
REMOVAL.............................14
INSTALLATION.........................15
TIRES / WHEELS
DIAGNOSIS AND TESTING - TIRE AND WHEEL
RUNOUT
Radial runout is the difference between the high
and low points on the tire or wheel (Fig. 1).
Lateral runout is thewobbleof the tire or
wheel.
Fig. 1 Checking Tire/Wheel/Hub Runout
1 - RADIAL RUNOUT
2 - LATERAL RUNOUT
VATIRES/WHEELS 22 - 1

Radial-ply tires must always be used in sets of
four. Under no circumstances should they be used on
the front only. They may be mixed with temporary
spare tires when necessary. A maximum speed of 50
MPH is recommended while a temporary spare is in
use.
Radial-ply tires have the same load-carrying capac-
ity as other types of tires of the same size. They also
use the same recommended inflation pressures.
The use of oversized tires, either in the front or
rear of the vehicle, can cause vehicle drive train fail-
ure. This could also cause inaccurate wheel speed
signals when the vehicle is equipped with Anti-Lock
Brakes.
The use of tires from different manufactures on the
same vehicle is NOT recommended. The proper tire
pressure should be maintained on all four tires.
DESCRIPTION - TIRE PRESSURE FOR HIGH
SPEEDS
Where speed limits allow the vehicle to be driven
at high speeds, correct tire inflation pressure is very
important. For speeds up to and including 120 km/h
(75 mph), tires must be inflated to the pressures
shown on the tire placard. For continuous speeds in
excess of 120 km/h (75 mph), tires must be inflated
to the maximum pressure specified on the tire side-
wall.
Vehicles loaded to the maximum capacity should
not be driven at continuous speeds above 75 mph
(120 km/h).
For emergency vehicles that are driven at speeds
over 90 mph (144 km/h), special high speed tires
must be used. Consult tire manufacturer for correct
inflation pressure recommendations.
DESCRIPTION - REPLACEMENT TIRES
The original equipment tires provide a proper bal-
ance of many characteristics such as:
²Ride
²Noise
²Handling
²Durability
²Tread life
²Traction
²Rolling resistance
²Speed capability
It is recommended that tires equivalent to the orig-
inal equipment tires be used when replacement is
needed.
Failure to use equivalent replacement tires may
adversely affect the safety and handling of the vehi-
cle.The use of oversize tires may cause interference
with vehicle components. Under extremes of suspen-
sion and steering travel, interference with vehicle
components may cause tire damage.
WARNING: FAILURE TO EQUIP THE VEHICLE WITH
TIRES HAVING ADEQUATE SPEED CAPABILITY
CAN RESULT IN SUDDEN TIRE FAILURE.
DESCRIPTION - TIRE INFLATION PRESSURES
Under inflation will cause rapid shoulder wear, tire
flexing, and possible tire failure (Fig. 12).
Over inflation will cause rapid center wear and
loss of the tire's ability to cushion shocks (Fig. 13).
Improper inflation can cause:
²Uneven wear patterns
²Reduced tread life
²Reduced fuel economy
²Unsatisfactory ride
Fig. 12 Under Inflation Wear
1 - THIN TIRE THREAD AREAS
Fig. 13 Over Inflation Wear
1 - THIN TIRE THREAD AREA
22 - 8 TIRES/WHEELSVA

²Vehicle drift
For proper tire pressure specification refer to the
Tire Inflation Pressure Chart provided with the vehi-
cles Owners Manual. A Certification Label on the
drivers side door pillar provides the minimum tire
and rim size for the vehicle. The label also list the
cold inflation pressure for these tires at full load
operation
Tire pressures have been chosen to provide safe
operation, vehicle stability, and a smooth ride. Tire
pressure should be checked cold once a month. Tire
pressure decreases as the ambient temperature
drops. Check tire pressure frequently when ambient
temperature varies widely.
Tire inflation pressures are cold inflation pressure.
The vehicle must sit for at least 3 hours to obtain the
correct cold inflation pressure reading. Or be driven
less than one mile after sitting for 3 hours. Tire
inflation pressures may increase from 2 to 6 pounds
per square inch (psi) during operation. Do not reduce
this normal pressure build-up.
WARNING: OVER OR UNDER INFLATED TIRES CAN
AFFECT VEHICLE HANDLING AND TREAD WEAR.
THIS MAY CAUSE THE TIRE TO FAIL SUDDENLY,
RESULTING IN LOSS OF VEHICLE CONTROL.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - PRESSURE
GAUGES
A quality air pressure gauge is recommended to
check tire pressure. After checking the air pressure,
replace valve cap finger tight.
DIAGNOSIS AND TESTING - 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 noise level during acceleration and
deceleration. The engine, differential and exhaust
noises will change as speed varies, while the tire
noise will usually remain constant.
DIAGNOSIS AND TESTING - TREAD WEAR
INDICATORS
Tread wear indicators are molded into the bottom
of the tread grooves. When tread depth is 1.6 mm
(1/16 in.), the tread wear indicators will appear as a
13 mm (1/2 in.) band (Fig. 14).Tire replacement is necessary when indicators
appear in two or more grooves or if localized balding
occurs.
DIAGNOSIS AND TESTING - TIRE WEAR PAT-
TERNS
Under inflation will cause wear on the shoulders of
tire. Over inflation will cause wear at the center of
tire.
Excessive camber causes the tire to run at an
angle to the road. One side of tread is then worn
more than the other (Fig. 15).
Excessive toe-in or toe-out causes wear on the
tread edges and a feathered effect across the tread
(Fig. 15).
Fig. 14 Tread Wear Indicators
1 - TREAD ACCEPTABLE
2 - TREAD UNACCEPTABLE
3 - WEAR INDICATOR
VATIRES/WHEELS 22 - 9