1996 Pontiac Sunfire Owner's Manual - Page 264

Treadwear The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one and a half (I 1/2) times as well on the government course as a tire graded IW. relative gm-hmrnce o tires depends The f upon the actual conditions oftheir use, however, and may depart significantly from the norm due to variations in driving habits, service practices and differences in road characteristics and climate. 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 rnate~alf the tire $0 o degenerate d redwe €ireMe, d excessive temperature can leead to sudden tire €aihre. The gradeC corresponds to a level of performance which all passenger car tires must meetunder the Federal Motor Vehicle Safety Standard No. 109. Grades B and A represent higher levelsof performance on the laboratory test wheel than theminimum required by law. Warning: The temperature grade for this tire is established for a tire that is properly inflated and not overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure. - *action - A, B, C The traction grades, from highest to lowest, are A, B, and C, and they represent the tire's ability to stop on wet pavement as measured under controlled con&tions on specified government test surfaces of asphalt and concrete. A tire markedC 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. 6-41