SERVICING AND MAINTENANCE 545
Tread Wear Indicators
Tread wear indicators are in the original equipment tires to
help you in determining when your tires should be replaced.Tire Tread
These indicators are molded into the bottom of the tread
grooves. They will appear as bands when the tread depth
becomes a 1/16 of an inch (1.6 mm). When the tread is worn to
the tread wear indicators, the tire should be replaced.
Refer to “Replacement Tires” in this section for further information.
Life Of Tire
The service life of a tire is dependent upon varying factors
including, but not limited to:
• Driving style.
• Tire pressure - Improper cold tire inflation pressures can
cause uneven wear patterns to develop across the tire
tread. These abnormal wear patterns will reduce tread life,
resulting in the need for earlier tire replacement.
• Distance driven.
• Performance tires, tires with a speed rating of V or higher, and Summer tires typically have a reduced tread life. Rota -
tion of these tires per the vehicle scheduled maintenance is
highly recommended.
1 — Worn Tire
2 — New Tire
WARNING!
Tires and the spare tire should be replaced after six
years, regardless of the remaining tread. Failure to follow
this warning can result in sudden tire failure. You could
lose control and have a collision resulting in serious
injury or death.
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546 SERVICING AND MAINTENANCE
(Continued)
NOTE:
Wheel Valve Stem must be replaced as well when installing
new tires due to wear and tear in existing tires.
Keep dismounted tires in a cool, dry place with as little expo-
sure to light as possible. Protect tires from contact with oil,
grease, and gasoline.
Replacement Tires
The tires on your new vehicle provide a balance of many
characteristics. They should be inspected regularly for wear
and correct cold tire inflation pressures. The manufacturer
strongly recommends that you use tires equivalent to the
originals in size, quality and performance when replacement
is needed. Refer to the paragraph on “Tread Wear Indica -
tors” in this section. Refer to the Tire and Loading Informa -
tion placard or the Vehicle Certification Label for the size
designation of your tire. The Load Index and Speed Symbol
for your tire will be found on the original equipment tire
sidewall.
See the Tire Sizing Chart example found in the “Tire Safety
Information” section of this manual for more information
relating to the Load Index and Speed Symbol of a tire. It is recommended to replace the two front tires or two rear
tires as a pair. Replacing just one tire can seriously affect
your vehicle’s handling. If you ever replace a wheel, make
sure that the wheel’s specifications match those of the orig
-
inal wheels.
It is recommended you contact an authorized tire dealer or
original equipment dealer with any questions you may have
on tire specifications or capability. Failure to use equivalent
replacement tires may adversely affect the safety, handling,
and ride of your vehicle.
WARNING!
• Do not use a tire, wheel size, load rating, or speed rating other than that specified for your vehicle. Some combi -
nations of unapproved tires and wheels may change
suspension dimensions and performance characteris -
tics, resulting in changes to steering, handling, and
braking of your vehicle. This can cause unpredictable
handling and stress to steering and suspension compo -
nents. You could lose control and have a collision
resulting in serious injury or death. Use only the tire
and wheel sizes with load ratings approved for your
vehicle.
SERVICING AND MAINTENANCE 547
Tire Types
All Season Tires — If Equipped
All Season tires provide traction for all seasons (Spring,
Summer, Fall, and Winter). Traction levels may vary
between different all season tires. All season tires can be
identified by the M+S, M&S, M/S or MS designation on the
tire sidewall. Use all season tires only in sets of four; failure
to do so may adversely affect the safety and handling of your
vehicle.Summer Or Three Season Tires — If Equipped
Summer tires provide traction in both wet and dry condi
-
tions, and are not intended to be driven in snow or on ice. If
your vehicle is equipped with Summer tires, be aware these
tires are not designed for Winter or cold driving conditions.
Install Winter tires on your vehicle when ambient tempera -
tures are less than 40°F (5°C) or if roads are covered with ice
or snow. For more information, contact an authorized dealer.
Summer tires do not contain the all season designation or
mountain/snowflake symbol on the tire sidewall. Use
Summer tires only in sets of four; failure to do so may
adversely affect the safety and handling of your vehicle.
• Never use a tire with a smaller load index or capacity,
other than what was originally equipped on your
vehicle. Using a tire with a smaller load index could
result in tire overloading and failure. You could lose
control and have a collision.
• Failure to equip your vehicle with tires having adequate speed capability can result in sudden tire
failure and loss of vehicle control.
CAUTION!
Replacing original tires with tires of a different size may
result in false speedometer and odometer readings.
WARNING! (Continued)
WARNING!
Do not use Summer tires in snow/ice conditions. You
could lose vehicle control, resulting in severe injury or
death. Driving too fast for conditions also creates the
possibility of loss of vehicle control. 7
SERVICING AND MAINTENANCE 549
Compact Spare Tire — If Equipped
The compact spare is for temporary emergency use only.
You can identify if your vehicle is equipped with a compact
spare by looking at the spare tire description on the Tire and
Loading Information Placard located on the driver’s side
door opening or on the sidewall of the tire. Compact spare
tire descriptions begin with the letter “T” or “S” preceding
the size designation. Example: T145/80D18 103M.
T, S = Temporary Spare Tire
Since this tire has limited tread life, the original equipment
tire should be repaired (or replaced) and reinstalled on your
vehicle at the first opportunity.
Do not install a wheel cover or attempt to mount a conven-
tional tire on the compact spare wheel, since the wheel is
designed specifically for the compact spare tire. Do not
install more than one compact spare tire and wheel on the
vehicle at any given time. Collapsible Spare Tire — If Equipped
The collapsible spare is for temporary emergency use only.
You can identify if your vehicle is equipped with a collaps
-
ible spare by looking at the spare tire description on the Tire
and Loading Information Placard located on the driver’s side
door opening or on the sidewall of the tire.
Collapsible spare tire description example: 165/80-17 101P.
Since this tire has limited tread life, the original equipment
tire should be repaired (or replaced) and reinstalled on your
vehicle at the first opportunity.
Inflate collapsible tire only after the wheel is properly
installed to the vehicle. Inflate the collapsible tire using the
electric air pump before lowering the vehicle.WARNING!
Compact and collapsible spares are for temporary
emergency use only. With these spares, do not drive
more than 50 mph (80 km/h). Temporary use spares have
limited tread life. When the tread is worn to the tread
wear indicators, the temporary use spare tire needs to be
replaced. Be sure to follow the warnings, which apply to
your spare. Failure to do so could result in spare tire
failure and loss of vehicle control.
7
550 SERVICING AND MAINTENANCE
Do not install a wheel cover or attempt to mount a conven-
tional tire on the collapsible spare wheel, since the wheel is
designed specifically for the collapsible spare tire.
Full Size Spare — If Equipped
The full size spare is for temporary emergency use only. This
tire may look like the originally equipped tire on the front or
rear axle of your vehicle, but it is not. This spare tire may
have limited tread life. When the tread is worn to the tread
wear indicators, the temporary use full size spare tire needs
to be replaced. Since it is not the same as your original equip -
ment tire, replace (or repair) the original equipment tire and
reinstall on the vehicle at the first opportunity. Limited Use Spare — If Equipped
The limited use spare tire is for temporary emergency use
only. This tire is identified by a label located on the limited
use spare wheel. This label contains the driving limitations
for this spare. This tire may look like the original equipped
tire on the front or rear axle of your vehicle, but it is not.
Installation of this limited use spare tire affects vehicle
handling. Since it is not the same as your original equipment
tire, replace (or repair) the original equipment tire and rein
-
stall on the vehicle at the first opportunity.
WARNING!
Compact and Collapsible spares are for temporary
emergency use only. With these spares, do not drive
more than 50 mph (80 km/h). Temporary use spares have
limited tread life. When the tread is worn to the tread
wear indicators, the temporary use spare tire needs to be
replaced. Be sure to follow the warnings, which apply to
your spare. Failure to do so could result in spare tire
failure and loss of vehicle control.
WARNING!
Limited use spares are for emergency use only.
Installation of this limited use spare tire affects vehicle
handling. With this tire, do not drive more than the
speed listed on the limited use spare wheel. Keep
inflated to the cold tire inflation pressures listed on your
Tire and Loading Information Placard located on the
driver’s side B-Pillar or the rear edge of the driver’s side
door. Replace (or repair) the original equipment tire at
the first opportunity and reinstall it on your vehicle.
Failure to do so could result in loss of vehicle control.
552 SERVICING AND MAINTENANCE
Dark Vapor Chrome, Black Satin Chrome, or Low Gloss
Clear Coat WheelsTire Chains (Traction Devices)
Use of traction devices require sufficient tire-to-body clear-
ance. Follow these recommendations to guard against
damage.
• Traction device must be of proper size for the tire, as recommended by the traction device manufacturer.
Please follow the table below for proper tire size, chain type,
and axle recommendations:
CAUTION!
If your vehicle is equipped with these specialty wheels, DO
NOT USE wheel cleaners, abrasives, or polishing compounds.
They will permanently damage this finish and such damage is
not covered by the New Vehicle Limited Warranty. HAND
WASH ONLY USING MILD SOAP AND WATER WITH A
SOFT CLOTH. Used on a regular basis; this is all that is
required to maintain this finish.
Vehicle Axle
Recommendations Tire Sizes
Chain Class
2500 Models Rear OnlyLT245/70R17E
LT275/70R18EU Class
2500 Power Wagon Models Rear OnlyLT285/70R17D U Class
3500 (Single Rear Wheel) Models Rear Only LT275/70R18E U Class
3500 (Dual Rear Wheel) Models Front/Rear LT235/80R17E U Class
WARNING!
Using tires of different size and type (M+S, Snow)
between front and rear axles can cause unpredictable
handling. You could lose control and have a collision.
556 SERVICING AND MAINTENANCE
Treadwear
The Treadwear grade is a comparative rating, based on
the wear rate of the tire when tested under controlled
conditions on a specified government test course. For
example, a tire graded 150 would wear one and one-half
times as well on the government course as a tire graded
100. The relative performance of tires depends upon the
actual conditions of their use, however, and may depart
significantly from the norm due to variations in driving
habits, service practices, and differences in road charac-
teristics and climate.
Traction Grades
The Traction grades, from highest to lowest, are AA, A, B,
and C. These grades represent the tire's ability to stop on
wet pavement, as measured under controlled conditions
on specified government test surfaces of asphalt and
concrete. A tire marked C may have poor traction perfor -
mance. Temperature Grades
The Temperature grades are A (the highest), B, and C,
representing the tire's resistance to the generation of heat
and its ability to dissipate heat, when tested under
controlled conditions on a specified indoor laboratory test
wheel.
Sustained high temperature can cause the material of the
tire to degenerate and reduce tire life, and excessive
temperature can lead to sudden tire failure. The grade C
corresponds to a level of performance, which all
passenger vehicle tires must meet under the Federal
Motor Vehicle Safety Standard No. 109. Grades B and A
represent higher levels of performance on the laboratory
test wheel, than the minimum required by law.WARNING!
The traction grade assigned to this tire is based on
straight-ahead braking traction tests, and does not
include acceleration, cornering, hydroplaning, or peak
traction characteristics.
SERVICING AND MAINTENANCE 557
STORING THE VEHICLE
If you are storing your vehicle for more than 21 days, we
recommend that you take the following steps to minimize
the drain on your vehicle's battery:
• Disconnect the negative cable from battery.
• Any time you store your vehicle or keep it out of service(i.e., vacation) for two weeks or more, run the air condi -
tioning system at idle for about five minutes in the fresh air
and high blower setting. This will ensure adequate system
lubrication to minimize the possibility of compressor
damage when the system is started again.
BODYWORK
Protection From Atmospheric Agents
Vehicle body care requirements vary according to
geographic locations and usage. Chemicals that make roads
passable in snow and ice and those that are sprayed on trees
and road surfaces during other seasons are highly corrosive
to the metal in your vehicle. Outside parking, which exposes
your vehicle to airborne contaminants, road surfaces on
which the vehicle is operated, extreme hot or cold weather
and other extreme conditions will have an adverse effect on
paint, metal trim, and underbody protection.
The following maintenance recommendations will enable
you to obtain maximum benefit from the corrosion resistance
built into your vehicle.
What Causes Corrosion?
Corrosion is the result of deterioration or removal of paint
and protective coatings from your vehicle.
The most common causes are:
• Road salt, dirt and moisture accumulation.
• Stone and gravel impact.
WARNING!
The temperature grade for this tire is established for a
tire that is properly inflated and not overloaded.
Excessive speed, under-inflation, or excessive loading,
either separately or in combination, can cause heat
buildup and possible tire failure.
7