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GM’s exclusive TPC Spec system considers over adozen critical specifications that impact the overallperformance of your vehicle, including brake systemperformance, ride and handling, traction control, and tirepressure monitoring performance. GM’s TPC Specnumber is molded onto the tire’s sidewall near the tiresize. If the tires have an all-season tread design,the TPC Spec number will be followed by an MS formud and snow. SeeTire Sidewall Labeling on page 6-47for additional information.
GM recommends replacing tires in sets of four. This isbecause uniform tread depth on all tires will helpkeep your vehicle performing most like it did when thetires were new. Replacing less than a full set of tires canaffect the braking and handling performance of yourvehicle. SeeTire Inspection and Rotation on page 6-62for information on proper tire rotation.
{WARNING:
Mixing tires could cause you to lose control of
your vehicle 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.
Your vehicle may have a compact spare tire and
wheel assembly. If the vehicle has a compact
spare tire and wheel, they have the same overall
diameter as your vehicle’s full-size tires and
wheels. Because they were designed and
developed for use on your vehicle, it is all right to
drive your vehicle with the compact spare installed
properly. Compact spare tires are designed for
temporary use only. SeeSpare Tire on page 6-90.
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{WARNING:
If you use bias-ply tires on the vehicle, thewheel rim flanges could develop cracks aftermany miles of driving. A tire and/or wheelcould fail suddenly, causing a crash. Useonly radial-ply tires with the wheels onthe vehicle.
If you must replace your vehicle’s tires with those thatdo not have a TPC Spec number, make sure theyare the same size, load range, speed rating, andconstruction type (radial and bias-belted tires) as yourvehicle’s original tires.
Vehicles that have a tire pressure monitoring systemcould give an inaccurate low-pressure warning ifnon-TPC Spec rated tires are installed on your vehicle.Non-TPC Spec rated tires may give a low-pressurewarning that is higher or lower than the proper warninglevel you would get with TPC Spec rated tires. SeeTire Pressure Monitor System on page 6-57.
Your vehicle’s original equipment tires are listed on theTire and Loading Information Label. SeeLoadingthe Vehicle on page 5-18, for more information aboutthe Tire and Loading Information Label and its locationon your vehicle.
Different Size Tires and Wheels
If you add wheels or tires that are a different size thanyour original equipment wheels and tires, this mayaffect the way your vehicle performs, including itsbraking, ride and handling characteristics, stability, andresistance to rollover. Additionally, if your vehiclehas electronic systems such as, antilock brakes, tractioncontrol, and electronic stability control, the performanceof these systems can be affected.
{WARNING:
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 6-64andAccessoriesand Modifications on page 6-3for additional information.
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Uniform Tire Quality Grading
Quality grades can be found where applicable onthe tire sidewall between tread shoulder andmaximum section width. For example:
Treadwear 200 Traction AA
Temperature A
The following information relates to the systemdeveloped by the United States National HighwayTraffic Safety Administration (NHTSA), whichgrades tires by treadwear, traction, andtemperature performance. This applies only tovehicles sold in the United States. The grades aremolded on the sidewalls of most passenger cartires. The Uniform Tire Quality Grading (UTQG)system does not apply to deep tread, winter-typesnow tires, space-saver, or temporary usespare tires, tires with nominal rim diameters of10 to 12 inches (25 to 30 cm), or to somelimited-production tires.
While the tires available on General Motorspassenger cars and light trucks may vary withrespect to these grades, they must also conformto federal safety requirements and additionalGeneral Motors Tire Performance Criteria (TPC)standards.
Treadwear
The treadwear grade is a comparative ratingbased on the wear rate of the tire when testedunder controlled conditions on a specifiedgovernment test course. For example, a tiregraded 150 would wear one and a half (1.5) timesas well on the government course as a tiregraded 100. The relative performance of tiresdepends upon the actual conditions of their use,however, and may depart significantly fromthe norm due to variations in driving habits, servicepractices, and differences in road characteristicsand climate.
Traction – AA, A, B, C
The traction grades, from highest to lowest, areAA, A, B, and C. Those grades represent the tire’sability to stop on wet pavement as measuredunder controlled conditions on specifiedgovernment test surfaces of asphalt and concrete.A tire marked C may have poor tractionperformance.
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Temperature – A, B, C
The temperature grades are A (the highest), B,and C, representing the tire’s resistance tothe generation of heat and its ability to dissipateheat when tested under controlled conditions on aspecified indoor laboratory test wheel. Sustainedhigh temperature can cause the material of the tireto degenerate and reduce tire life, and excessivetemperature can lead to sudden tire failure.The grade C corresponds to a level of performancewhich all passenger car tires must meet underthe Federal Motor Vehicle Safety StandardNo. 109. Grades B and A represent higher levelsof performance on the laboratory test wheelthan the minimum required by law. It should benoted that the temperature grade for this tireis established for a tire that is properly inflated andnot overloaded. Excessive speed, underinflation,or excessive loading, either separately or incombination, can cause heat buildup and possibletire failure.
Wheel Alignment and Tire Balance
The tires and wheels on your vehicle were alignedand balanced carefully at the factory to give you thelongest tire life and best overall performance.Adjustments to wheel alignment and tire balancing willnot be necessary on a regular basis. However, ifyou notice unusual tire wear or your vehicle pulling toone side or the other, the alignment might need tobe checked. If you notice your vehicle vibrating whendriving on a smooth road, the tires and wheelsmight need to be rebalanced. See your dealer/retailerfor proper diagnosis.
Wheel Replacement
Replace any wheel that is bent, cracked or badly rustedor corroded. If wheel nuts keep coming loose, the wheel,wheel bolts and wheel nuts should be replaced. If thewheel leaks air, replace it. Some aluminum wheels cansometimes be repaired. See your GM dealer/retailer ifany of these conditions exist.
Your GM dealer/retailer will know the kind of wheelyou need.
Each new wheel should have the same load-carryingcapacity, diameter, width, offset and be mountedthe same way as the one it replaces.
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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 originalequipment parts. This way, you will be sure to have theright wheel, wheel bolts, wheel nuts, and TPMSsensors for your vehicle.
{WARNING:
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 problemswith bearing life, brake cooling, speedometer orodometer calibration, headlamp aim, bumper height,vehicle ground clearance, and tire or tire chainclearance to the body and chassis.
If your vehicle is a professional model, the wheels havea unique offset and bolt hole diameter. Each of thewheels on the professional vehicle have eight wheelsnuts. The wheels on the non-professional vehiclehave five wheel nuts. SeeChanging a Flat Tire onpage 6-80for more information.
Used Replacement Wheels
{WARNING:
Putting a used wheel on the 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
{WARNING:
Do not use tire chains. 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 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 find traction devices that will fit, install
them on the front tires.
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 outslowly. But if you should ever have a blowout, hereare a few tips about what to expect and what to do:
If a front tire fails, the flat tire creates a drag that pullsthe vehicle toward that side. Take your foot off theaccelerator pedal and grip the steering wheel firmly.Steer to maintain lane position, and then gently brake toa stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like askid and may require the same correction you woulduse in a skid. In any rear blowout remove your foot fromthe accelerator pedal. Get the vehicle under controlby steering the way you want the vehicle to go. It maybe very bumpy and noisy, but you can still steer. Gentlybrake to a stop, well off the road if possible.
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{WARNING:
Lifting a vehicle and getting under it to do
maintenance or repairs is dangerous without the
appropriate safety equipment and training. If a jack
is provided with the vehicle, it is designed only for
changing a flat tire. If it is used for anything else,
you or others could be badly injured or killed if the
vehicle slips off the jack. If a jack is provided with
the vehicle, only use it for changing a flat tire.
This vehicle may come with a jack and spare tire or atire sealant and compressor kit. To use the jack andspare tire, follow the instructions below. To use the tiresealant and compressor kit, seeTire Sealant andCompressor Kit on page 6-71.
Tire Sealant and Compressor Kit
{WARNING:
Idling a vehicle in an enclosed area with poor
ventilation is dangerous. Engine exhaust may
enter the vehicle. Engine exhaust contains Carbon
Monoxide (CO) which cannot be seen or smelled.
It can cause unconsciousness and even death.
Never run the engine in an enclosed area that has
no fresh air ventilation. For more information, see
Engine Exhaust on page 3-34.
{WARNING:
Over-inflating a tire could cause the tire to rupture
and you or others could be injured. Be sure to
read and follow the tire sealant and compressor kit
instructions and inflate the tire to its recommended
pressure. Do not exceed the recommended
pressure.
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{WARNING:
Storing the tire sealant and compressor kit or
other equipment in the passenger compartment of
the vehicle could cause injury. In a sudden stop or
collision, loose equipment could strike someone.
Store the tire sealant and compressor kit in its
original location.
If this vehicle has a tire sealant and compressor kit,there may not be a spare tire, tire changing equipment,and on some vehicles there may not be a place tostore a tire.
The tire sealant and compressor can be used totemporarily seal punctures up to1⁄4inch (6 mm) in thetread area of the tire. It can also be used to inflatean under inflated tire.
If the tire has been separated from the wheel, hasdamaged sidewalls, or has a large puncture, the tire istoo severely damaged for the tire sealant andcompressor kit to be effective. SeeRoadside Service onpage 8-7.
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