1998 Cadillac Seville Owner's Manual - Page 322

Treadwear The treadwear grade is comparative rating based on a the wear rateof the tire when tested under controlled test conditions on a specified government course. For example, a tire graded 150 would wear one and a half (1 1/2) times as well on the government course as tire a graded 100. The relative performanceof tires depends upon the actual conditionsof their use, however, and may depart significantly from norm due to variations the in driving habits, service practices and differences in road characteristics and climate. Temperature -- A, B, C Traction -- AA, A, B, C The temperature grades are (the highest),B, and C, A representing the tire's resistance to the generation of heat and its ability to dissipate heat when tested under a controlled conditions on specified indoor laboratory test wheel. Sustained high temperature cause the can material of the tire to degenerate and reduce tire life, an 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 performance on the of laboratory test wheel than minimum required by law. the Warning: The temperature gradefor 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. The traction grades, from highest to lowest, are A, B, AA, and C. Those grades represent the tire's ability to stop on wet pavement as measured under controlled conditions on of specified government test surfaces asphalt and concrete. A tire marked C may have poor traction performance. Warning: The traction grade assigned to this tire based is on braking (straight ahead) traction tests and does not include acceleration, cornering, hydroplaning, or peak traction characteristics.