1994 Cadillac Fleetwood Owner's Manual - Page 310

Uniform Tire Quality Grading The following information relates to thesystem developed by the United States National Highway TrafficSafety Administration which grades tires by treadwear, traction and temperature performance. (This applies only to vehicles soldin the United States.) Treadwear The treadwear grade is a comparative rating based on the wear rate of the tirewhen tested under controlled conditions on a specified government test course. For example, a tiregraded 150 would wear one and a half (1 1/2) times as wellon 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 from the norm due tovariations in driving habits, service practices differences and 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 stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tiremarked C may have poor 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 abilityto 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 degenerateand reduce tire life, and excessive temperature can lead to sudden tire failure. The gradeC corresponds to alevel of performance which all passenger car tires must meet under the Federal Motor Vehicle Safety Standard No. 109. Grades B and A represent higher levels of performance on the laboratory test wheel than the minimum required by law. 297