(C) Aspect Ratio:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 60, as
shown in item C of the illustration, it would mean
that the tire’s sidewall is 60 percent as high as
it is wide.
(D) Construction Code
:A letter code is used to
indicate the type of ply construction in the tire. The
letter R means radial ply construction; the letter D
means diagonal or bias ply construction; and the
letter B means belted-bias ply construction.
(E) Rim Diameter
:Diameter of the wheel in
inches.
(F) Service Description
:These characters
represent the load range and speed rating of the
tire. The load index represents the load carry
capacity a tire is certi ed to carry. The load index
can range from 1 to 279. The speed rating is
the maximum speed a tire is certi ed to carry
a load. Speed ratings range from A to Z.
Tire Terminology and De nitions
Air Pressure:The amount of air inside the
tire pressing outward on each square inch of the
tire. Air pressure is expressed in pounds per
square inch (psi) or kilopascal (kPa).
Accessory Weight
:This means the combined
weight of optional accessories. Some examples of
optional accessories are, automatic transmission,
power steering, power brakes, power windows,
power seats, and air conditioning.
Aspect Ratio
:The relationship of a tire’s height
to its width.
Belt
:A rubber coated layer of cords that is
located between the plies and the tread. Cords
may be made from steel or other reinforcing
materials.
Bead
:The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the rim.
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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 5-68.
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 4-22.
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 in ation pressure.
See “Tire and Loading Information Label”
underLoading the Vehicle on page 4-22.
In ation - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-in ation or over-in ation is all right.
It is not. If your tires do not have enough air
(under-in ation), you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air (over-in ation),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazards
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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 in ated to the in ation
pressure recommended by the vehicle manufacturer
on the vehicle placard or tire in ation pressure label.
(If your vehicle has tires of a different size than the
size indicated on the vehicle placard or tire in ation
pressure label, you should determine the proper
tire in ation 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 signi cantly under-in ated.
Accordingly, when the low tire pressure telltale
illuminates, you should stop and check your tires as
soon as possible, and in ate them to the proper pressure.
Driving on a signi cantly under-in ated tire causes the
tire to overheat and can lead to tire failure. Under-in ation
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-in ation
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 ash 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 5-59for
additional information.
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Using the DIC, tire pressure levels can be viewed by
the driver. For additional information and details
about the DIC operation and displays seeDIC Operation
and Displays (With DIC Buttons) on page 3-54orDIC
Operation and Displays (Without DIC Buttons) on
page 3-60andDIC Warnings and Messages on
page 3-64.
The low tire pressure warning light may come on in cool
weather when the vehicle is rst 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 in ated 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 in ation pressure for
your vehicle’s tires when they are cold. SeeLoading the
Vehicle on page 4-22, for an example of the Tire and
Loading Information label and its location on your vehicle.
Also seeInflation - Tire Pressure on page 5-56.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 5-63andTires on page 5-49.
Notice:Using non-approved tire sealants could
damage the Tire Pressure Monitor System (TPMS)
sensors. TPMS sensor damage caused by using
an incorrect tire sealant is not covered by the
vehicle warranty. Always use the GM approved
tire sealant available through your dealer/retailer.
Your vehicle, when new, may have included a
factory-installed Tire Sealant and Compressor Kit.
This kit uses a GM approved liquid tire sealant.
SeeTire Sealant and Compressor Kit on page 5-73.
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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 in ation 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.
Buying New Tires
GM has developed and matched speci c 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
Speci cation (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 speci cations 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 an MS
for mud and snow. SeeTire Sidewall Labeling
on page 5-50for additional information.
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GM recommends replacing tires in sets of four.
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 5-63
for 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 all wheels.
It is all right to drive with your compact
spare temporarily, as it was developed for
use on your vehicle. SeeCompact Spare
Tire on page 5-100.
{CAUTION:
If you use bias-ply tires on the vehicle, the
wheel rim anges 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.
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 5-58.
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Your vehicle’s original equipment tires are listed
on the Tire and Loading Information Label.
SeeLoading the Vehicle on page 4-22, 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 may 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 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
Saturn speci c wheel and tire systems
developed for your vehicle, and have them
properly installed by a Saturn certi ed
technician.
SeeBuying New Tires on page 5-65andAccessories
and Modifications on page 5-3for additional information.
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Used Replacement Wheels
{CAUTION:
Putting a used wheel on your vehicle is
dangerous. You cannot know how it has been
used or how far it has been driven. It could fail
suddenly and cause a crash. If you have to
replace a wheel, use a new Saturn original
equipment wheel.
Tire Chains
{CAUTION:
Do not use tire chains. There is not enough
clearance. Tire chains used on a vehicle
without the proper amount of clearance can
CAUTION: (Continued)
CAUTION: (Continued)
cause damage to the brakes, suspension or
other vehicle parts. The area damaged by the
tire chains could cause you to lose control of
the 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 the
vehicle and tire size combination and road
conditions. Follow that manufacturer’s
instructions. To help avoid damage to the
vehicle, drive slowly, readjust or remove the
device if it is contacting the vehicle, and do
not spin the vehicle’s wheels. If you do nd
traction devices that will t, install them on
the front tires.
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