Page 388 of 480

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.
6-68
Page 389 of 480

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.
6-69
Page 406 of 480
10. Remove any rust or dirtfrom the wheel bolts,mounting surfaces, andspare wheel.
{WARNING:
Rust or dirt on a wheel, or on the parts to which it
is fastened, can make wheel nuts become loose
after time. The wheel could come off and cause
an accident. When changing a wheel, remove any
rust or dirt from places where the wheel attaches
to the vehicle. In an emergency, use a cloth or a
paper towel to do this; but be sure to use a
scraper or wire brush later, if needed, to get all the
rust or dirt off. SeeChanging a Flat Tire on
page 6-80.
11. Place the spare tire on the wheel-mounting surface.
{WARNING:
Never use oil or grease on bolts or nuts because
the nuts might come loose. The vehicle’s wheel
could fall off, causing a crash.
12. Put the wheel nuts backon with the roundedend of the nuts towardthe wheel. Tighten eachnut by hand until thewheel is held againstthe hub.
6-86