Radial Ply Tire:A pneumatic tire in which the
ply cords that extend to the beads are laid at
90 degrees to the centerline of the tread.
Rim
:A metal support for a tire and upon which
the tire beads are seated.
Sidewall
:The portion of a tire between the tread
and the bead.
Speed Rating
:An alphanumeric code assigned to
a tire indicating the maximum speed at which a
tire can operate.
Traction
:The friction between the tire and the
road surface. The amount of grip provided.
Tread
:The portion of a tire that comes into
contact with the road.
Treadwear Indicators
:Narrow bands, sometimes
called wear bars, that show across the tread of
a tire when only 1/16 inch (1.6 mm) of tread
remains. SeeWhen It Is Time for New Tires
on page 5-71.UTQGS (Uniform Tire Quality Grading
Standards)
:A tire information system that
provides consumers with ratings for a tire’s
traction, temperature, and treadwear. Ratings are
determined by tire manufacturers using government
testing procedures. The ratings are molded into
the sidewall of the tire. SeeUniform Tire Quality
Grading on page 5-74.
Vehicle Capacity Weight
:The number of
designated seating positions multiplied by
150 lbs (68 kg) plus the rated cargo load.
SeeLoading the Vehicle on page 4-19.
Vehicle Maximum Load on the Tire
:Load on
an individual tire due to curb weight, accessory
weight, occupant weight, and cargo weight.
Vehicle Placard
:A label permanently attached
to a vehicle showing the vehicle’s capacity
weight and the original equipment tire size and
recommended inflation pressure. See “Tire and
Loading Information Label” underLoading the
Vehicle on page 4-19.
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Tire Pressure Monitor System
The Tire Pressure Monitor System (TPMS) uses radio
and sensor technology to check tire pressure levels.
The TPMS sensors monitor the air pressure in
your vehicle’s tires and transmit tire pressure
readings to a receiver located in the vehicle.
Each tire, including the spare (if provided), should be
checked monthly when cold and inflated to the inflation
pressure recommended by the vehicle manufacturer
on the vehicle placard or tire inflation pressure label.
(If your vehicle has tires of a different size than the
size indicated on the vehicle placard or tire inflation
pressure label, you should determine the proper
tire inflation pressure for those tires.)
As an added safety feature, your vehicle has been
equipped with a tire pressure monitoring system (TPMS)
that illuminates a low tire pressure telltale when one
or more of your tires is significantly under-inflated.
Accordingly, when the low tire pressure telltale
illuminates, you should stop and check your tires
as soon as possible, and inflate them to the proper
pressure. Driving on a significantly under-inflated
tire causes the tire to overheat and can lead to tire
failure. Under-inflation also reduces fuel efficiency and
tire tread life, and may affect the vehicle’s handling
and stopping ability.Please note that the TPMS is not a substitute for proper
tire maintenance, and it is the driver’s responsibility to
maintain correct tire pressure, even if under-inflation
has not reached the level to trigger illumination of
the TPMS low tire pressure telltale.
Your vehicle has also been equipped with a TPMS
malfunction indicator to indicate when the system is
not operating properly. The TPMS malfunction indicator
is combined with the low tire pressure telltale. When the
system detects a malfunction, the telltale will flash for
approximately one minute and then remain continuously
illuminated. This sequence will continue upon
subsequent vehicle start-ups as long as the malfunction
exists.
When the malfunction indicator is illuminated, the
system may not be able to detect or signal low tire
pressure as intended. TPMS malfunctions may occur
for a variety of reasons, including the installation of
replacement or alternate tires or wheels on the vehicle
that prevent the TPMS from functioning properly. Always
check the TPMS malfunction telltale after replacing one
or more tires or wheels on your vehicle to ensure that
the replacement or alternate tires and wheels allow the
TPMS to continue to function properly.
SeeTire Pressure Monitor Operation on page 5-65for
additional information.
5-64
The low tire pressure warning light may come on in
cool weather when the vehicle is first started, and then
turn off as you start to drive. This could be an early
indicator that the air pressure in the tire(s) are getting
low and need to be inflated to the proper pressure.
A Tire and Loading Information label, attached to
your vehicle, shows the size of your vehicle’s original
equipment tires and the correct inflation pressure
for your vehicle’s tires when they are cold. SeeLoading
the Vehicle on page 4-19, for an example of the Tire
and Loading Information label and its location on
your vehicle. Also seeInflation - Tire Pressure on
page 5-62.
Your vehicle’s TPMS can warn you about a low tire
pressure condition but it does not replace normal
tire maintenance. SeeTire Inspection and Rotation
on page 5-69andTires on page 5-54.
Notice:Liquid tire sealants could damage the Tire
Pressure Monitor System (TPMS) sensors. Sensor
damage caused by using a tire sealant is not
covered by your warranty. Do not use liquid
tire sealants.TPMS Malfunction Light and Message
The TPMS will not function properly if one or more of
the TPMS sensors are missing or inoperable. When the
system detects a malfunction, the low tire warning light
flashes for about one minute and then stays on for the
remainder of the ignition cycle. A DIC warning message
is also displayed. The low tire warning light and DIC
warning message come on at each ignition cycle until
the problem is corrected. Some of the conditions that
can cause the malfunction light and DIC message to
come on are:
•One of the road tires has been replaced with the
spare tire. The spare tire does not have a TPMS
sensor. The TPMS malfunction light and DIC
message should go off once you re-install the
road tire containing the TPMS sensor.
•The TPMS sensor matching process was started but
not completed or not completed successfully after
rotating the vehicle’s tires. The DIC message and
TPMS malfunction light should go off once the TPMS
sensor matching process is performed successfully.
See “TPMS Sensor Matching Process” later in this
section.
5-66
When It Is Time for New Tires
Various factors, such as maintenance, temperatures,
driving speeds, vehicle loading, and road conditions,
influence when you need new tires.
One way to tell when it
is time for new tires is to
check the treadwear
indicators, which appear
when your tires have only
1/16 inch (1.6 mm) or less
of tread remaining.
Some commercial truck tires, including
Goodyear LT225/75R16 G949 RSA and
Goodyear LT225/75R16 G933 RSD, may not
have treadwear indicators. If the tires do not have
treadwear indicators, replace the tires when the
tread depth is down to 1/8 inch (3.2 mm) for the
front tires, or 1/16 inch (1.6 mm) for the rear tires.You need new tires if any of the following statements
are true:•You can see the indicators at three or more places
around the tire.
•You can see cord or fabric showing through the
tire’s rubber.
•The tread or sidewall is cracked, cut, or snagged
deep enough to show cord or fabric.
•The tire has a bump, bulge, or split.
•The tire has a puncture, cut, or other damage that
cannot be repaired well because of the size or
location of the damage.
The rubber in tires degrades over time, even if they are
not being used. This is also true for the spare tire, if your
vehicle has one. Multiple conditions affect how fast this
aging takes place, including temperatures, loading
conditions, and inflation pressure maintenance. With
proper care and maintenance tires will typically wear out
before they degrade due to age. If you are unsure about
the need to replace your tires as they get older, consult
the tire manufacturer for more information.
5-71
Buying New Tires
GM has developed and matched specific tires for
your vehicle. The original equipment tires installed
on your vehicle, when it was new, were designed
to meet General Motors Tire Performance Criteria
Specification (TPC spec) system rating. If you need
replacement tires, GM strongly recommends that you
get tires with the same TPC Spec rating. This way,
your vehicle will continue to have tires that are designed
to give the same performance and vehicle safety,
during normal use, as the original tires.
GM’s exclusive TPC Spec system considers over a
dozen critical specifications that impact the overall
performance of your vehicle, including brake system
performance, ride and handling, traction control, and
tire pressure monitoring performance. GM’s TPC Spec
number is molded onto the tire’s sidewall near the tire
size. If the tires have an all-season tread design, the TPC
spec number will be followed by a MS, for mud and snow.
SeeTire Sidewall Labeling on page 5-55for additional
information.
GM recommends replacing tires in sets of four
(or six if your vehicle has dual rear wheels). This is
because uniform tread depth on all tires will help keep
your vehicle performing most like it did when the tires
were new. Replacing less than a full set of tires can affect
the braking and handling performance of your vehicle.
SeeTire Inspection and Rotation on page 5-69for
information on proper tire rotation.{CAUTION:
Mixing tires could cause you to lose control
while driving. If you mix tires of different
sizes, brands, or types (radial and bias-belted
tires) the vehicle may not handle properly,
and you could have a crash. Using tires of
different sizes, brands, or types may also
cause damage to your vehicle. Be sure to
use the correct size, brand, and type of tires
on your vehicle’s wheels.
{CAUTION:
If you use bias-ply tires on the vehicle, the
wheel rim flanges could develop cracks after
many miles of driving. A tire and/or wheel
could fail suddenly, causing a crash. Use
only radial-ply tires with the wheels on the
vehicle.
5-72
If you must replace your vehicle’s tires with those that
do not have a TPC Spec number, make sure they
are the same size, load range, speed rating, and
construction type (radial and bias-belted tires) as
your vehicle’s original tires.
Vehicles that have a tire pressure monitoring system
could give an inaccurate low-pressure warning if
non-TPC Spec rated tires are installed on your vehicle.
Non-TPC Spec rated tires may give a low-pressure
warning that is higher or lower than the proper warning
level you would get with TPC Spec rated tires.
SeeTire Pressure Monitor System on page 5-64.
Your vehicle’s original equipment tires are listed on the
Tire and Loading Information label. SeeLoading the
Vehicle on page 4-19, for more information about
the Tire and Loading Information label and its location
on your vehicle.Different Size Tires and Wheels
If you add wheels or tires that are a different size than
your original equipment wheels and tires, this could affect
the way your vehicle performs, including its braking, ride
and handling characteristics, stability, and resistance
to rollover. Additionally, if your vehicle has electronic
systems such as anti-lock brakes, rollover airbags,
traction control, and electronic stability control, the
performance of these systems can be affected.
{CAUTION:
If you add different sized wheels, your vehicle may
not provide an acceptable level of performance and
safety if tires not recommended for those wheels
are selected. You may increase the chance that you
will crash and suffer serious injury. Only use GM
specific wheel and tire systems developed for your
vehicle, and have them properly installed by a GM
certified technician.
SeeBuying New Tires on page 5-72andAccessories
and Modifications on page 5-3for additional information.
5-73
Tire Chains
{CAUTION:
If your vehicle has dual wheels or P245/70R17 or
LT245/75R16 size tires, do not use tire chains.
They can damage your vehicle because there is not
enough clearance. Tire chains used on a vehicle
without the proper amount of clearance can cause
damage to the brakes, suspension, or other vehicle
parts. The area damaged by the tire chains could
cause you to lose control of your vehicle and you or
others may be injured in a crash.
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
conditions. Follow that manufacturer’s instructions.
CAUTION: (Continued)
CAUTION: (Continued)
To help avoid damage to your vehicle, drive
slowly, readjust, or remove the device if it is
contacting your vehicle, and do not spin the
vehicle’s wheels.
If you do find traction devices that will fit, install
them on the rear tires.
Notice:If your vehicle does not have dual
wheels and has a tire size other than P245/70R17 or
LT245/75R16, use tire chains only where legal and
only when you must. Use chains that are the proper
size for your tires. Install them on the tires of the rear
axle. Do not use chains on the tires of the front axle.
Tighten them as tightly as possible with the ends
securely fastened. Drive slowly and follow the chain
manufacturer’s instructions. If you can hear the
chains contacting your vehicle, stop and retighten
them. If the contact continues, slow down until it
stops. Driving too fast or spinning the wheels with
chains on will damage your vehicle.
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4. When the tire has been lowered, pull the tire toward
you so you can reach the tire retainer and pull it up
through the wheel opening.
If you have a vehicle which was completed from a
cab and chassis, refer to the information from
body supplier/installer.
The spare tire is a full-size tire, like the other tires
on the vehicle.
5. Put the spare tire near the flat tire.
Removing the Flat Tire and
Installing the Spare Tire
If your vehicle has plastic wheel nut caps, loosen
them by turning the wheel wrench counterclockwise.
The wheel nut caps are designed to remain with
the center cap. Remove the center cap.
If the wheel has a smooth center piece, place the chisel
end of the wheel wrench in the slot on the wheel and
gently pry it out.
1. Do a safety check before proceeding. SeeChanging
a Flat Tire on page 5-80for more information.
2. Loosen all the wheel nuts with the wheel wrench.
Do not remove them yet.
5-84