Q:What is wrong with this?
A:The belt is twisted across the body.
{CAUTION:
You can be seriously injured by a twisted belt.
In a crash, you would not have the full width
of the belt to spread impact forces. If a belt
is twisted, make it straight so it can work
properly, or ask your dealer/retailer to x it.
1-22
Tire Sidewall Labeling
Useful information about a tire is molded into its
sidewall. The examples below show a typical
passenger car tire and a compact spare tire
sidewall.
(A) Tire Size
:The tire size is a combination of
letters and numbers used to de ne a particular
tire’s width, height, aspect ratio, construction type
and service description. See the “Tire Size”
illustration later in this section for more detail.(B) DOT (Department of Transportation)
:The Department of Transportation (DOT) code
indicates that the tire is in compliance with the
U.S. Department of Transportation Motor Vehicle
Safety Standards.
(C) Tire Identi cation Number (TIN)
:The letters
and numbers following DOT code are the Tire
Identi cation Number (TIN). The TIN shows
the manufacturer and plant code, tire size, and
date the tire was manufactured. The TIN is molded
onto both sides of the tire, although only one
side may have the date of manufacture.
(D) Tire Ply Material
:The type of cord and
number of plies in the sidewall and under the tread.
(E) Uniform Tire Quality Grading (UTQG)
:Tire
manufacturers are required to grade tires based
on three performance factors: treadwear,
traction and temperature resistance. For more
information seeUniform Tire Quality Grading on
page 5-65.
(F) Maximum Cold In ation Load Limit
:Maximum load that can be carried and the
maximum pressure needed to support that load.
For information on recommended tire pressure
seeInflation - Tire Pressure on page 5-55
andLoading Your Vehicle on page 4-19.Passenger Car Tire Example
5-50
(A) Temporary Use Only:The compact spare
tire or temporary use tire has a tread life of
approximately 3,000 miles (5 000 km) and should
not be driven at speeds over 65 mph (105 km/h).
The compact spare tire is for emergency use when
a regular road tire has lost air and gone at. See
Compact Spare Tire on page 5-81andIf a Tire
Goes Flat on page 5-69.(B) Tire Ply Material
:The type of cord and
number of plies in the sidewall and under the tread.
(C) Tire Identi cation Number (TIN)
:The
Tire Identi cation Number (TIN). The TIN shows
the manufacturer and plant code, tire size,
and date the tire was manufactured. The TIN
is molded onto both sides of the tire, although
only one side may have the date of manufacture.
(D) Maximum Cold In ation Load Limit
:Maximum load that can be carried and the
maximum pressure needed to support that load.
SeeCompact Spare Tire on page 5-81and
Loading Your Vehicle on page 4-19.
(E) Tire In ation
:The temporary use tire or
compact spare tire should be in ated to 60 psi
(420 kPa). For more information on tire pressure
and in ation seeInflation - Tire Pressure on
page 5-55.
(F) Tire Size
:A combination of letters and
numbers de ne a tire’s width, height, aspect
ratio, construction type and service description.
The letter T as the rst character in the tire
size means the tire is for temporary use only.
Compact Spare Tire Example
5-51
Tire Size
The following illustration shows an example of a
typical passenger car tire size.
(A) Passenger (P-Metric) Tire
:The United States
version of a metric tire sizing system. The letter P
as the rst character in the tire size means a
passenger vehicle tire engineered to standards
set by the U. S. Tire and Rim Association.
(B) Tire Width
:The three-digit number indicates
the tire section width in millimeters from sidewall
to sidewall.
(C) Aspect Ratio
:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 70, as
shown in item C of the illustration, it would mean
that the tire’s sidewall is 70% 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 the speed rating
of a tire. The load range represents the load carry
capacity a tire is certi ed to carry. 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.
5-52
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.
Bias Ply Tire
:A pneumatic tire in which the plies
are laid at alternate angles less than 90 degrees
to the centerline of the tread.
Cold Tire Pressure
:The amount of air pressure
in a tire, measured in pounds per square inch
(psi) or kilopascals (kPa) before a tire has built up
heat from driving. SeeInflation - Tire Pressure
on page 5-55.
Curb Weight
:The weight of a motor vehicle with
standard and optional equipment including the
maximum capacity of fuel, oil, and coolant,
but without passengers and cargo.
DOT Markings
:A code molded into the sidewall
of a tire signifying that the tire is in compliance
with the U.S. Department of Transportation (DOT)
motor vehicle safety standards. The DOT code
includes the Tire Identi cation Number (TIN),an alphanumeric designator which can also
identify the tire manufacturer, production plant,
brand, and date of production.
GVWR
:Gross Vehicle Weight Rating.
SeeLoading Your Vehicle on page 4-19.
GAWR FRT
:Gross Axle Weight Rating for
the front axle. SeeLoading Your Vehicle on
page 4-19.
GAWR RR
:Gross Axle Weight Rating for the rear
axle. SeeLoading Your Vehicle on page 4-19.
Intended Outboard Sidewall
:The side of
an asymmetrical tire, that must always face
outward when mounted on a vehicle.
Kilopascal (kPa)
:The metric unit for air pressure.
Light Truck (LT-Metric) Tire
:A tire used on light
duty trucks and some multipurpose passenger
vehicles.
Load Index
:An assigned number ranging from
1 to 279 that corresponds to the load carrying
capacity of a tire.
Maximum In ation Pressure
:The maximum air
pressure to which a cold tire can be in ated. The
maximum air pressure is molded onto the sidewall.
5-53
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,
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 speci c wheel and tire systems developed
for your vehicle, and have them properly
installed by a GM certi ed technician.
SeeBuying New Tires on page 5-63andAccessories
and Modifications on page 5-3for additional information.
Uniform Tire Quality Grading
Quality grades can be found where applicable
on the tire sidewall between tread shoulder
and maximum selection width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the Unites States National
Highway Traffic Safety Administration (NHTSA),
which grades tires by treadwear, traction, and
temperature performance. This applies only
to vehicles sold in the United States. The grades
are molded on the sidewalls of most passenger
car tires. The Uniform Tire Quality Grading
(UTQG) system does not apply to deep tread,
winter-type snow tires, space-saver, or temporary
use spare tires, tires with nominal rim diameters
of 10 to 12 inches (25 to 30 cm), or to some
limited-production tires.
While the tires available on General Motors
passenger cars and light trucks may vary with
respect to these grades, they must also conform
to federal safety requirements.
5-65
Wheel Alignment and Tire Balance
The tires and wheels on your vehicle were aligned and
balanced carefully at the factory to give you the longest
tire life and best overall performance. Adjustments to
wheel alignment and tire balancing will not be necessary
on a regular basis. However, if you notice unusual tire
wear or your vehicle pulling to one side or the other,
the alignment might need to be checked. If you notice
your vehicle vibrating when driving on a smooth road,
the tires and wheels might need to be rebalanced.
See your dealer/retailer for proper diagnosis.
Wheel Replacement
Replace any wheel that is bent, cracked, or badly rusted
or corroded. If wheel nuts keep coming loose, the wheel,
wheel bolts, and wheel nuts should be replaced. If the
wheel leaks air, replace it (except some aluminum
wheels, which can sometimes be repaired). See your
dealer/retailer if any of these conditions exist.
Your dealer/retailer will know the kind of wheel you need.
Each new wheel should have the same load-carrying
capacity, diameter, width, offset, and be mounted
the same way as the one it replaces.If you need to replace any of your wheels, wheel bolts,
wheel nuts, or Tire Pressure Monitor System (TPMS)
sensors, replace them only with new GM original
equipment parts. This way, you will be sure to have the
right wheel, wheel bolts, wheel nuts, and TPMS sensors
for your vehicle.
{CAUTION:
Using the wrong replacement wheels, wheel
bolts, or wheel nuts on your vehicle can be
dangerous. It could affect the braking and
handling of your vehicle, make your tires
lose air and make you lose control. You could
have a collision in which you or others could
be injured. Always use the correct wheel,
wheel bolts, and wheel nuts for replacement.
Notice:The wrong wheel can also cause problems
with bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper height,
vehicle ground clearance, and tire or tire chain
clearance to the body and chassis.
SeeChanging a Flat Tire on page 5-70for more
information.
5-67