1996 Buick Century Owner's Manual - Page 249

Treadwear The treadwear grade isa 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 (1 1/2) times as well on the government course as a tire graded 100. The relativeperformance of tires depends upon the actual conditionsof their use, however, and may depart significantlyfrom the norm due to variations in driving habits, service practices differences in and road characteristics and climate. Temperature -- A, B, C Traction -- 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 dissipateheat when tested under controlled conditionson a specified indoorlaboratory test wheel. Sustained high temperature cause the can material of the tire to degenerate reduce tirelife, and and excessive temperaturecan lead to sudden tire failure. The gradeC corresponds toa level of performance which all passenger car tires must meet under the Federal Motor Vehicle Safety StandardNo. 109. Grades B and A represent higher levels performance on the of laboratory test wheel than the minimum required by law. is Warning: The temperature grade for this tire established fora tire that is properlyinflated and not overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tirefailure. The traction grades, from highest to lowest,are A, B, and C, and they represent the tire's ability to stop wet on pavement as measured under controlled conditions on specified government test surfaces asphalt and concrete. of A tire marked C may have poor traction performance. Warning: The traction grade assigned tothis tire is based on braking (straightahead) traction tests and does not include cornering (turning) traction. Wheel Alignment and Tire Balance The wheels on your vehicle were aligned and balanced carefully atthe factory to give you the longest tire life and best overall performance. 6-43