1995 Pontiac Grand Am Owner's Manual - Page 251

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 leadto sudden tire failure. The grade C corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Vehicle SafetyStandard No. 109. Grades B and A represent higherlevels of performance on the laboratory test wheel thanthe minimum required by law. - While the tires available as standard optional or equipment on General Motors vehicles vary with may respect to these grades, all such tires meet General Motors performance standards and have been approved for use on General Motors vehicles. All passenger type (P Metric) tires must conform to Federal safety requirements in addition to these grades. Wheel Alignment and Tire Balance The wheels on your vehicle were aligned and balanced carefully atthe factory to give you the longest tire life and best overall performance. In most cases, you will not need to have your wheels aligned again. However, if you notice unusual tire wear or your vehicle pulling one or the other, the way If alignment may need to be reset. you notice your vehicle vibrating when driving on smooth road, your a wheels may need be rebalanced. to Warning: The temperature grade for this tire is established for a tire that is properly inflated and not overl'oaded.Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure. These grades are molded on the sidewalls of passenger car tires.