flat tire DODGE RAM 2002 Service User Guide

circumstances necessitate that a child, or an adult
with certain medical conditions be placed in the front
passenger seating position. Refer to the owner's man-
ual in the vehicle glove box for specific recommenda-
tions concerning the specific circumstances where the
passenger airbag on/off switch should be used to dis-
able the passenger airbag.
Deployment of the airbags depends upon the angle
and severity of the impact. The airbag system is
designed to deploy upon a frontal impact within a
thirty degree angle from either side of the vehicle
center line. Deployment is not based upon vehicle
speed; rather, deployment is based upon the rate of
deceleration as measured by the forces of gravity (G
force) upon the airbag system impact sensor, which is
integral to the ACM. When a frontal impact is severe
enough, the microprocessor in the ACM signals the
inflator units of both airbag modules to deploy the
airbags. During a frontal vehicle impact, the knee
blockers work in concert with properly fastened and
adjusted seat belts to restrain both the driver and
the front seat passenger in the proper position for an
airbag deployment. The knee blockers also absorb
and distribute the crash energy from the driver and
the front seat passenger to the structure of the
instrument panel.
Typically, the driver and front seat passenger recall
more about the events preceding and following a col-
lision than they have of the airbag deployment itself.
This is because the airbag deployment and deflation
occur so rapidly. In a typical 48 kilometer-per-hour
(30 mile-per-hour) barrier impact, from the moment
of impact until both airbags are fully inflated takes
about 40 milliseconds. Within one to two seconds
from the moment of impact, both airbags are almost
entirely deflated. The times cited for these events are
approximations, which apply only to a barrier impact
at the given speed. Actual times will vary somewhat,
depending upon the vehicle speed, impact angle,
severity of the impact, and the type of collision.
When the ACM monitors a problem in any of the
airbag system circuits or components, it stores a
fault code or Diagnostic Trouble Code (DTC) in its
memory circuit and sends an electronic message to
the EMIC to turn on the airbag indicator. Proper
testing of the airbag system components, the
Chrysler Collision Detection (CCD) data bus, the
data bus message inputs to and outputs from the
EMIC or the ACM, as well as the retrieval or erasure
of a DTC from the ACM requires the use of a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of all of the factory-installed passenger restraints,
including the airbag system.WARNING
WARNING: THE AIRBAG SYSTEM IS A SENSITIVE,
COMPLEX ELECTROMECHANICAL UNIT. BEFORE
ATTEMPTING TO DIAGNOSE OR SERVICE ANY AIR-
BAG SYSTEM OR RELATED STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENTS YOU MUST FIRST DISCONNECT
AND ISOLATE THE BATTERY NEGATIVE (GROUND)
CABLE. THEN WAIT TWO MINUTES FOR THE SYS-
TEM CAPACITOR TO DISCHARGE BEFORE FUR-
THER SYSTEM SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE
TO DO THIS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
WARNING: THE DRIVER AIRBAG INFLATOR UNIT
CONTAINS SODIUM AZIDE AND POTASSIUM
NITRATE. THESE MATERIALS ARE POISONOUS
AND EXTREMELY FLAMMABLE. CONTACT WITH
ACID, WATER, OR HEAVY METALS MAY PRODUCE
HARMFUL AND IRRITATING GASES (SODIUM
HYDROXIDE IS FORMED IN THE PRESENCE OF
MOISTURE) OR COMBUSTIBLE COMPOUNDS. THE
PASSENGER AIRBAG UNIT CONTAINS ARGON GAS
PRESSURIZED TO OVER 2500 PSI. DO NOT
ATTEMPT TO DISMANTLE AN AIRBAG UNIT OR
TAMPER WITH ITS INFLATOR. DO NOT PUNCTURE,
INCINERATE, OR BRING INTO CONTACT WITH
ELECTRICITY. DO NOT STORE AT TEMPERATURES
EXCEEDING 93É C (200É F).
WARNING: REPLACE AIRBAG SYSTEM COMPO-
NENTS ONLY WITH PARTS SPECIFIED IN THE
DAIMLERCHRYSLER MOPAR PARTS CATALOG.
SUBSTITUTE PARTS MAY APPEAR INTERCHANGE-
ABLE, BUT INTERNAL DIFFERENCES MAY RESULT
IN INFERIOR OCCUPANT PROTECTION.
WARNING: THE FASTENERS, SCREWS, AND
BOLTS ORIGINALLY USED FOR THE AIRBAG SYS-
TEM COMPONENTS HAVE SPECIAL COATINGS
AND ARE SPECIFICALLY DESIGNED FOR THE AIR-
BAG SYSTEM. THEY MUST NEVER BE REPLACED
WITH ANY SUBSTITUTES. ANY TIME A NEW FAS-
TENER IS NEEDED, REPLACE IT WITH THE COR-
RECT FASTENERS PROVIDED IN THE SERVICE
PACKAGE OR SPECIFIED IN THE
DAIMLERCHRYSLER MOPAR PARTS CATALOG.
BR/BERESTRAINTS 8O - 3
RESTRAINTS (Continued)

(2) From the underside of the steering wheel,
remove the two screws that secure the driver airbag
to the steering wheel armature (Fig. 10).
(3) Pull the driver airbag away from the steering
wheel far enough to access the two wire harness con-
nectors at the back of the airbag.
(4) Disconnect the clockspring horn switch pigtail
wire connector from the horn switch feed pigtail wire
connector, which is located at the back of the driver
airbag.
CAUTION: Do not pull on the clockspring pigtail
wire to disengage the connector from the driver air-
bag inflator connector receptacle.
(5) The clockspring driver airbag pigtail wire con-
nector is a tight snap-fit into the airbag inflator con-
nector receptacle, which is located at the back of the
driver airbag. Firmly grasp and pull or gently pry on
the clockspring driver airbag wire harness connector
to disconnect it from the airbag inflator connector
receptacle.
(6) Remove the driver airbag from the steering
wheel.
(7) If the driver airbag has been deployed, the
clockspring and the steering column must be
replaced. (Refer to 8 - ELECTRICAL/RESTRAINTS/CLOCKSPRING - REMOVAL) (Refer to 19 - STEER-
ING/COLUMN - REMOVAL).
DISASSEMBLY
The horn switch is integral to the driver airbag
trim cover. If either component is faulty or damaged,
the entire driver airbag trim cover and horn switch
unit must be replaced.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
Fig. 10 Driver Airbag Remove/Install
1 - DRIVER SIDE AIRBAG MODULE
2 - HORN SWITCH FEED WIRE CONNECTOR3 - CLOCKSPRING WIRE HARNESS CONNECTOR
4 - SCREW (2)
BR/BERESTRAINTS 8O - 15
DRIVER AIRBAG (Continued)

the entire driver airbag trim cover and horn switch
unit must be replaced.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
WARNING: THE HORN SWITCH IS INTEGRAL TO
THE DRIVER AIRBAG UNIT. SERVICE OF THIS UNIT
SHOULD BE PERFORMED ONLY BY
DAIMLERCHRYSLER-TRAINED AND AUTHORIZED
DEALER SERVICE TECHNICIANS. FAILURE TO
TAKE THE PROPER PRECAUTIONS OR TO FOL-
LOW THE PROPER PROCEDURES COULD RESULT
IN ACCIDENTAL, INCOMPLETE, OR IMPROPER AIR-
BAG DEPLOYMENT AND POSSIBLE OCCUPANT
INJURIES.
WARNING: USE EXTREME CARE TO PREVENT ANY
FOREIGN MATERIAL FROM ENTERING THE DRIVER
AIRBAG, OR BECOMING ENTRAPPED BETWEEN
THE DRIVER AIRBAG CUSHION AND THE DRIVER
AIRBAG TRIM COVER. FAILURE TO OBSERVE THIS
WARNING COULD RESULT IN OCCUPANT INJURIES
UPON AIRBAG DEPLOYMENT.
WARNING: THE DRIVER AIRBAG TRIM COVER
MUST NEVER BE PAINTED. REPLACEMENT TRIM
COVERS ARE SERVICED IN THE ORIGINAL COL-
ORS. PAINT MAY CHANGE THE WAY IN WHICH THE
MATERIAL OF THE TRIM COVER RESPONDS TO AN
AIRBAG DEPLOYMENT. FAILURE TO OBSERVE
THIS WARNING COULD RESULT IN OCCUPANT
INJURIES UPON AIRBAG DEPLOYMENT.
(1) Carefully position the driver airbag in the trim
cover. Be certain that the horn switch feed and
ground pigtail wires are not pinched between the air-
bag housing and the trim cover locking blocks.
(2) Engage the upper and lower trim cover locking
blocks with the lip of the driver airbag housing, then
engage the locking blocks on each side of the trim
cover with the lip of the housing. Be certain that
each of the locking blocks is fully engaged on the lip
of the airbag housing (Fig. 14).(3) Reinstall the horn switch ground pigtail wire
eyelet terminal over the left upper airbag housing
stud.
(4) Reinstall the upper and lower airbag trim cover
retainers over the airbag housing studs. Be certain
that the tabs on the retainers are engaged in the
retainer slots of the trim cover locking blocks (Fig.
13).
(5) Install and tighten the nuts that secure the
trim cover retainers to the airbag housing studs.
Tighten the nuts to 10 N´m (90 in. lbs.).
(6) Route the horn switch feed pigtail wire
between the inflator housing and the right upper air-
bag housing stud.
(7) Reinstall the plastic wire retainer onto the
right upper airbag housing stud to capture horn
switch feed pigtail wire.
(8) Reinstall the driver airbag onto the steering
wheel. (Refer to 8 - ELECTRICAL/RESTRAINTS/
DRIVER AIRBAG - INSTALLATION).
INSTALLATION
The following procedure is for replacement of a
faulty or damaged driver airbag. If the driver airbag
has been deployed, the clockspring and the steering
column assembly must also be replaced. (Refer to 8 -
Fig. 14 Driver Airbag Trim Cover Locking Blocks
Engaged
1 - LIP
2 - TRIM COVER
3 - HORN SWITCH
4 - AIRBAG HOUSING
5 - LOCKING BLOCK
BR/BERESTRAINTS 8O - 17
DRIVER AIRBAG (Continued)

(9) Install piston spring in retainer and on top of
piston. Concave side of spring faces downward
(toward piston).
(10) Install the spacer ring and wave spring into
the retainer. Be sure spring is completely seated in
retainer groove.
(11) Install pressure plate (Fig. 223). Ridged side
of plate faces downward (toward piston) and flat side
toward clutch pack.
(12) Install first clutch disc in retainer on top of
pressure plate. Then install a clutch plate followed
by a clutch disc until entire clutch pack is installed
(4 discs and 3 plates are required) (Fig. 223).
(13) Install the reaction plate.
(14) Install selective snap-ring. Be sure snap-ring
is fully seated in retainer groove.
(15) Using a suitable gauge bar and dial indicator,
measure clutch pack clearance (Fig. 225).
(a) Position gauge bar across the clutch drum
with the dial indicator pointer on the pressure
plate (Fig. 225).
(b) Using two small screw drivers, lift the pres-
sure plate and release it.
(c) Zero the dial indicator.
(d) Lift the pressure plate until it contacts the
snap-ring and record the dial indicator reading.
Clearance should be 0.635 - 0.914 mm (0.025 - 0.036
in.). If clearance is incorrect, steel plates, discs, selective
snap ring and pressure plates may have to be changed.
The selective snap ring thicknesses are:
²0.107 - 0.109 in.
²0.098 - 0.100 in.
²0.095 - 0.097 in.
²0.083 - 0.085 in.
²0.076 - 0.078 in.
²0.071 - 0.073 in.
²0.060 - 0.062 in.
(16) Coat rear clutch thrust washer with petro-
leum jelly and install washer over input shaft and
into clutch retainer (Fig. 226). Use enough petroleum
jelly to hold washer in place.
(17) Set rear clutch aside for installation during
final assembly.
Fig. 224 Pressing Input Shaft Into Rear Clutch
Retainer
1 - INPUT SHAFT
2 - REAR CLUTCH RETAINER
3 - PRESS RAMFig. 225 Checking Rear Clutch Pack Clearance
1 - DIAL INDICATOR
2 - PRESSURE PLATE
3 - SNAP-RING
4-STAND
5 - REAR CLUTCH
6 - GAUGE BAR
Fig. 226 Installing Rear Clutch Thrust Washer
1 - REAR CLUTCH RETAINER
2 - REAR CLUTCH THRUST WASHER
21 - 206 AUTOMATIC TRANSMISSION - 46REBR/BE
REAR CLUTCH (Continued)

(11) Install pressure plate (Fig. 223). Ridged side
of plate faces downward (toward piston) and flat side
toward clutch pack.
(12) Install first clutch disc in retainer on top of
pressure plate. Then install a clutch plate followed
by a clutch disc until entire clutch pack is installed
(4 discs and 3 plates are required) (Fig. 223).
(13) Install the reaction plate.
(14) Install selective snap-ring. Be sure snap-ring
is fully seated in retainer groove.
(15) Using a suitable gauge bar and dial indicator,
measure clutch pack clearance (Fig. 217).
(a) Position gauge bar across the clutch drum
with the dial indicator pointer on the pressure
plate (Fig. 217).
(b) Using two small screw drivers, lift the pres-
sure plate and release it.
(c) Zero the dial indicator.
(d) Lift the pressure plate until it contacts the
snap-ring and record the dial indicator reading.
Clearance should be 0.635 - 0.914 mm (0.025 -
0.036 in.). If clearance is incorrect, steel plates, discs,
selective snap ring and pressure plates may have to
be changed.
The selective snap ring thicknesses are:
²0.107 - 0.109 in.
²0.098 - 0.100 in.
²0.095 - 0.097 in.
²0.083 - 0.085 in.
²0.076 - 0.078 in.
²0.071 - 0.073 in.
²0.060 - 0.062 in.
(16) Coat rear clutch thrust washer with petro-
leum jelly and install washer over input shaft and
into clutch retainer (Fig. 218). Use enough petroleum
jelly to hold washer in place.
(17) Set rear clutch aside for installation during
final assembly.
REAR SERVO
DESCRIPTION
The rear (low/reverse) servo consists of a single
stage or diameter piston and a spring loaded plug.
The spring is used to cushion the application of the
rear (low/reverse) band.
OPERATION
While in the de-energized state (no pressure
applied), the piston is held up in its bore by the pis-
ton spring. The plug is held down in its bore, in the
piston, by the plug spring. When pressure is applied
to the top of the piston, the plug is forced down in its
bore, taking up any clearance. As the piston moves, it
causes the plug spring to compress, and the pistonmoves down over the plug. The piston continues to
move down until it hits the shoulder of the plug and
fully applies the band. The period of time from the
initial application, until the piston is against the
shoulder of the plug, represents a reduced shocking
of the band that cushions the shift.
DISASSEMBLY
(1) Remove small snap-ring and remove plug and
spring from servo piston (Fig. 219).
(2) Remove and discard servo piston seal ring.
Fig. 217 Checking Rear Clutch Pack Clearance
1 - DIAL INDICATOR
2 - PRESSURE PLATE
3 - SNAP-RING
4-STAND
5 - REAR CLUTCH
6 - GAUGE BAR
Fig. 218 Installing Rear Clutch Thrust Washer
1 - REAR CLUTCH RETAINER
2 - REAR CLUTCH THRUST WASHER
21 - 378 AUTOMATIC TRANSMISSION - 47REBR/BE
REAR CLUTCH (Continued)

TIRES/WHEELS
TABLE OF CONTENTS
page page
TIRES/WHEELS
DIAGNOSIS AND TESTING - TIRE AND
WHEEL RUNOUT......................1
STANDARD PROCEDURE
STANDARD PROCEDURE -
TIRE ROTATION.......................2
STANDARD PROCEDURE - MATCH
MOUNTING...........................3
STANDARD PROCEDURE - TIRE AND
WHEEL BALANCE......................4
TIRES
DESCRIPTION
DESCRIPTION - SPARE TIRE - TEMPORARY...6
DESCRIPTION - TIRES..................6
DESCRIPTION - RADIAL-PLY TIRES........6
DESCRIPTION - TIRE PRESSURE FOR
HIGH SPEEDS.........................7
DESCRIPTION - REPLACEMENT TIRES.....7
DESCRIPTION - TIRE INFLATION
PRESSURES..........................7
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - PRESSURE
GAUGES.............................8
DIAGNOSIS AND TESTING - TREAD WEAR
INDICATORS..........................8
DIAGNOSIS AND TESTING - TIRE WEAR
PATTERNS...........................8DIAGNOSIS AND TESTING - TIRE NOISE
OR VIBRATION........................9
STANDARD PROCEDURE - REPAIRING
LEAKS...............................9
SPECIFICATIONS
TIRE REVOLUTIONS PER MILE...........9
SPARE TIRE
DESCRIPTION.........................10
WHEELS
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING
WHEEL INSPECTION..................11
STANDARD PROCEDURE - DUAL REAR
WHEEL INSTALLATION.................11
SPECIFICATIONS
TORQUE CHART......................11
STUDS
REMOVAL.............................12
INSTALLATION.........................12
WHEEL COVER
REMOVAL.............................12
INSTALLATION
INSTALLATION - REAR.................12
INSTALLATION - FRONT................12
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.
Radial runout of more than 1.5 mm (.060 inch)
measured at the center line of the tread may cause
the vehicle to shake.
Lateral runout of more than 2.0 mm (.080 inch)
measured near the shoulder of the tire may cause the
vehicle to shake.
Sometimes radial runout can be reduced. Relocate
the wheel and tire assembly on the mounting studs
(See Method 1). If this does not reduce runout to an
acceptable level, the tire can be rotated on the wheel.
(See Method 2).
Fig. 1 Checking Tire/Wheel/Hub Runout
1 - RADIAL RUNOUT
2 - LATERAL RUNOUT
BR/BETIRES/WHEELS 22 - 1

METHOD 1 (RELOCATE WHEEL ON HUB)
(1) Drive vehicle a short distance to eliminate tire
flat spotting from a parked position.
(2) Check wheel bearings and adjust if adjustable
or replace if necessary.
(3) Check the wheel mounting surface.
(4) Relocate wheel on the mounting, two studs
over from the original position.
(5) Tighten wheel nuts until all are properly
torqued, to eliminate brake distortion.
(6) Check radial runout. If still excessive, mark
tire sidewall, wheel, and stud at point of maximum
runout and proceed to Method 2.
METHOD 2 (RELOCATE TIRE ON WHEEL)
NOTE: Rotating the tire on wheel is particularly
effective when there is runout in both tire and
wheel.
(1) Remove tire from wheel and mount wheel on
service dynamic balance machine.
(2) Check wheel radial runout (Fig. 2) and lateral
runout (Fig. 3).
²STEEL WHEELS: Radial runout 0.040 in., Lat-
eral runout 0.045 in. (maximum)
²ALUMINUM WHEELS: Radial runout 0.030 in.,
Lateral runout 0.035 in. (maximum)
(3)
If point of greatest wheel lateral runout is near
original chalk mark, remount tire 180 degrees. Recheck
runout, Refer to match mounting procedure.
STANDARD PROCEDURE
STANDARD PROCEDURE - TIRE ROTATION
Tires on the front and rear axles operate at differ-
ent loads and perform different steering, driving, and
braking functions. For these reasons, the tires wear
at unequal rates. They may also develop irregular
wear patterns. These effects can be reduced by rotat-
ing the tires according to the maintenance schedule
in the Owners Manual. This will improve tread life,
traction and maintain a smooth quiet ride.
The recommended method of tire rotation is (Fig.
4). Other methods can be used, but may not provide
the same tire longevity benefits.
Dual wheel vehicles require a different tire rota-
tion pattern. Refer to (Fig. 5) for the proper tire rota-
tion with dual wheels.
Fig. 2 Radial Runout
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
Fig. 3 Lateral Runout
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
Fig. 4 Tire Rotation Pattern
22 - 2 TIRES/WHEELSBR/BE
TIRES/WHEELS (Continued)

TIRES
DESCRIPTION
DESCRIPTION - SPARE TIRE - TEMPORARY
The temporary spare tire is designed for emer-
gency use only. The original tire should be repaired
or replaced at the first opportunity, then reinstalled.
Do not exceed speeds of 50 M.P.H. when using the
temporary spare tire. Refer to Owner's Manual for
complete details.
DESCRIPTION - TIRES
Tires are designed and engineered for each specific
vehicle. They provide the best overall performance
for normal operation. The ride and handling charac-
teristics match the vehicle's requirements. With
proper care they will give excellent reliability, trac-
tion, skid resistance, and tread life.
Driving habits have more effect on tire life than
any other factor. Careful drivers will obtain in most
cases, much greater mileage than severe use or care-
less drivers. A few of the driving habits which will
shorten the life of any tire are:
²Rapid acceleration
²Severe brake applications
²High speed driving
²Excessive speeds on turns
²Striking curbs and other obstacles
Radial-ply tires are more prone to irregular tread
wear. It is important to follow the tire rotation inter-
val shown in the section on Tire Rotation, (Refer to
22 - TIRES/WHEELS - STANDARD PROCEDURE).
This will help to achieve a greater tread life.
TIRE IDENTIFICATION
Tire type, size, aspect ratio and speed rating are
encoded in the letters and numbers imprinted on the
side wall of the tire. Refer to the chart to decipher
the tire identification code (Fig. 11).
Performance tires have a speed rating letter after
the aspect ratio number. The speed rating is not
always printed on the tire sidewall. These ratings
are:
²Qup to 100 mph
²Rup to 106 mph
²Sup to 112 mph
²Tup to 118 mph
²Uup to 124 mph
²Hup to 130 mph
²Vup to 149 mph
²Zmore than 149 mph (consult the tire manu-
facturer for the specific speed rating)An All Season type tire will have eitherM+S,M
&SorM±S(indicating mud and snow traction)
imprinted on the side wall.
TIRE CHAINS
Tire snow chains may be used oncertainmodels.
Refer to the Owner's Manual for more information.
DESCRIPTION - RADIAL-PLY TIRES
Radial-ply tires improve handling, tread life and
ride quality, and decrease rolling resistance.
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.
Fig. 11 Tire Identification
22 - 6 TIRES/WHEELSBR/BE

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
²Vehicle driftFor 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
Fig. 12 Under Inflation Wear
1 - THIN TIRE THREAD AREAS
Fig. 13 Over Inflation Wear
1 - THIN TIRE THREAD AREA
BR/BETIRES/WHEELS 22 - 7
TIRES (Continued)

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 - 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
PATTERNS
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. 15 Tire Wear Patterns
Fig. 14 Tread Wear Indicators
1 - TREAD ACCEPTABLE
2 - TREAD UNACCEPTABLE
3 - WEAR INDICATOR
22 - 8 TIRES/WHEELSBR/BE
TIRES (Continued)