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
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 5-70andAccessories
and Modifications on page 5-3for additional information.
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Uniform Tire Quality Grading
Quality grades can be found where applicable on
the tire sidewall between tread shoulder and
maximum section width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United 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 and additional
General Motors Tire Performance Criteria (TPC)
standards.
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 a half (1.5) 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 characteristics
and climate.
Traction – AA, A, B, C
The traction grades, from highest to lowest, are AA,
A, B, and C. Those 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 performance.
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.
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Temperature – A, B, C
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 car 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 temperature grade for this tire
is established for a tire that is properly in ated
and not overloaded. Excessive speed,
underin ation, or excessive loading, either
separately or in combination, can cause heat
buildup and possible tire failure.
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 if any of these conditions exist.
Your dealer 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
or wheel nuts, replace them only with new GM original
equipment parts. This way, you will be sure to have the
right wheel, wheel bolts and wheel nuts for your vehicle.
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{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.Whenever a wheel, wheel bolt or wheel nut is
replaced on a dual wheel setup, check the wheel
nut torque after 100, 1,000 and 6,000 miles
(160, 1 600 and 10 000 km) of driving. For proper
torque, see “Wheel Nut Torque” underCapacities
and Specifications on page 5-110.
SeeChanging a Flat Tire on page 5-78for more
information.
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 GM original
equipment wheel.
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Tire Chains
{CAUTION:
If your vehicle has dual wheels or P245/75R16
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
CAUTION: (Continued)
CAUTION: (Continued)
conditions. Follow that manufacturer’s
instructions. 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 nd traction devices that will t,
install them on the rear tires.
Notice:If your vehicle does not have dual wheels
and has a tire size other than P245/75R16 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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If a Tire Goes Flat
It is unusual for a tire to blowout while you are driving,
especially if you maintain your vehicle’s tires properly.
If air goes out of a tire, it is much more likely to leak out
slowly. But if you should ever have a blowout, here
are a few tips about what to expect and what to do:
If a front tire fails, the flat tire creates a drag that pulls
the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you would
use in a skid. In any rear blowout remove your foot from
the accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop, well off the road if possible.{CAUTION:
Lifting a vehicle and getting under it to do
maintenance or repairs is dangerous without
the appropriate safety equipment and training.
The jack provided with your vehicle is
designed only for changing a at tire. If it is
used for anything else, you or others could be
badly injured or killed if the vehicle slips off
the jack. Use the jack provided with your
vehicle only for changing a at tire.
If a tire goes flat, the next part shows how to use the
jacking equipment to change a flat tire safely.
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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 the body
supplier/installer.
The spare tire is a full-size tire, like the other tires on
your vehicle.
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 5-78for more information.
2. With the DOWN side facing you, use the ratchet
and wheel wrench to loosen all the wheel nuts.
Do not remove them yet.
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7. Make sure the tire is stored securely. Push, pull (A),
and then try to turn (B) the tire. If the tire moves,
use the ratchet to tighten the cable.
You will hear two clicks when the tire is up all
the way.
8. Return the jacking equipment to the proper location.
Secure the items and replace the jack cover.
Spare Tire
Your vehicle, when new, had a fully-inflated spare tire.
A spare tire may lose air over time, so check its
inflation pressure regularly. SeeInflation - Tire Pressure
on page 5-60andLoading Your Vehicle on page 4-20
for information regarding proper tire inflation and loading
your vehicle. For instruction on how to remove, install
or store a spare tire, seeRemoving the Flat Tire and
Installing the Spare Tire on page 5-82andStoring a Flat
or Spare Tire and Tools on page 5-93.
After installing the spare tire on your vehicle, you should
stop as soon as possible and make sure the spare is
correctly inflated. The spare tire is made to perform well
at speeds up to 70 mph (112 km/h) at the recommended
inflation pressure, so you can finish your trip.
Have the damaged or flat road tire repaired or replaced
as soon as you can and installed back onto your
vehicle. This way, a spare tire will be available in case
you need it again. Do not mix tires and wheels of
different sizes, because they will not fit. Keep your spare
tire and its wheel together.
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