1997 GMC Safari Owner's Manual - Page 304

Traction -- A, B, C The traction grades, from highest to lowest, are B, and A, C, and they represent the tire's ability to stop on wet pavement as measured under controlled conditions on speclfed government test surfaces asphalt and concrete. of A tire marked C may have poor traction performance. Warning: The traction grade assigned to this tire is based on braking (straightahead) traction tests and does not include cornering (turning) traction. overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure. Wheel Alignment and Tire Balance The wheels on your vehicle were aligned and balanced carefully at the factory to give you the longest tire life and best overall performance. Scheduled wheel alignment and wheel balancing are not needed. However, if you notice unusual tire wear or your vehicle pulling one way or the other, the alignment may need to be reset. If you notice your vehicle vibrating when driving on a smooth road, your wheels may need to berebalanced. 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 dissipate heatwhen tested under controlled conditions on a specifiedindoor 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 performance of 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 that is properly inflated and not tire Wheel Replacement Replace any wheel that is bent, cracked, or badly rusted or corroded. If wheel nuts keep coming loose, thewheel, 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 GM dealer if any of these conditions exist. Your dealer will know the kind of wheel you need.