1993 Pontiac Grand Am Owner's Manual - Page 237

Warning: The temperature grade for this tire is established for a tire that is The traction grades, from highest to The temperature grades are A (the properly inflated and not overloaded. lowest are: A, B, and C. They represent highest), B, and C, representing the the tire's ability to stop on wet pavement tire's resistance to the generation heat Excessive speed, underinflation,or of excessive loading, either separately in or as measured under controlled conditions and its ability to dissipate heat when combination, can cause heat buildup on specified government test surfacesof tested under controlled conditions on a and possible tire failure. asphalt and concrete. A tire marked C specified indoor laboratory test wheel. may have poor traction performance. Sustained high temperature can cause Those grades are molded on the the material of the tire to degenerate and sidewalls of passenger car tires. Warning: The traction grade assigned to this tire is based on braking (straight- reduce tire life, and excessive While the tires available as standard or temperature can lead to sudden tire ahead) traction tests and does not optional equipment on General Motors failure. The grade C corresponds to a include cornering (turning) traction. vehicles may vary with respect to these level of performance which all grades, all such tires meet General passenger car tires must meet under the Motors performance standards and have Federal Motor Vehicle Safety Standard been approved for use on General No. 109. Grades B and A represent Motors vehicles. All passenger type higher levels of performance onthe (P Metric) tires must conform to Federal laboratory test wheel than the minimum safety requirements in addition to these required by law. grades. Traction-A, B, C Temperature-A, B, C