1998 Buick Skylark Owner's Manual - Page 267

controlled conditions on a specified indoor laboratory The treadwear grade is a comparative rating based on test wheel. Sustained high temperature can cause the material of the tire to degenerate and reduce tire life, and the wear rateof the tire when tested under controlled conditions on a specified government test course. For excessive temperature can lead to sudden tire failure. of The gradeC corresponds to a level performance example, a tire graded150 would wear one and a half (1 1/2) times as well on the government course as a tire which all passenger car tires must meet under the No. Federal Motor Vehicle Safety Standard 109. Grades of graded 100. The relative performance tires depends B and A represent higher levels performance on the of upon the actual conditions of their use, however, and laboratory test wheel than the minimum requiredlaw. by may depart significantly from the norm duevariations to Warning: The temperature grade for this tire is in driving habits, service practices and differences in established for a tire that properly inflated and not is road characteristics and climate. overloaded. Excessive speed, underinflation, or Traction A, B, C excessive loading, either separately or in combination, can cause heat buildup and possible tire failure. The traction grades, from highest to lowest, are B, and A, C, and they represent the tire's ability to stop on wet Wheel Alignment and Tire Balance pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. The wheels on your vehicle were aligned and balanced carefully at the factory to give you the longestlife tire A tire marked C may have poor traction performance. and best overall performance. Warning: The traction grade assigned this tireis based to Treadwear -- on braking (straight ahead) traction tests and does not include cornering (turning) traction. Temperature A, B, C The temperature grades are (the highest),B, and c', A representing the tire's resistance the generationof to heat andits ability to dissipate heat when tested under -- Scheduled wheel align mt and wheel balancing are nox needed. However,if you nbtice unusual tire wear or your vehicle pulling one way or the other, the alignment If may need to be reset. you notice your vehicle vibrating when driving on a smooth road, your wheels may need to be rebalanced. 6-44