1994 Cadillac Seville Owner's Manual - Page 308

Treadwear The treadwear grade is acomparative rating based on the wear rate of the tire when tested undercontrolled conditions on a specified government test course. For example, a tire graded 150 would wear one and a half (1 1/2) times as well on thegovernment course as a tire graded 100. The relative performance of tires depends upon the actual conditions of their use, however,and may depart significantly fromthe norm due tovariations in driving habits, service practices and differences in road characteristics and climate. Traction A, B, C The traction grades, from highest to lowest are: A, B, and C. They represent the tire's abilityto stopon wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may havepoor traction performance. Warning: The traction grade assigned to this tire is based on braking (straight-ahead) traction tests and does not include cornering (turning) traction. - Temperature -A, B, C The temperaturegrades are A (the highest), B, and C, representing the tire's resistance to thegeneration of heat and its ability to dissipate heat when tested under controlled conditions on a specifiedindoor laboratory test wheel. Sustained high temperature can cause the material of the tire to degenerateand reduce tire life, and excessive temperature can lead to sudden tire failure. The grade.C corresponds to a levelof performance which all passengercar tires must meet under the Federal Motor Vehicle Safety Standard No. 109. Grades B and A represent higher levels of performance on thelaboratory test wheel than the minimum required by law. Warning: The temperaturegrade 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. These grades are molded on thesidewalls of passenger car tires. - 295