1998 Buick Park Avenue Owner's Manual - Page 326

''I+he brcadwear grade is a comparative rating based Q ~ Z t tze wcx rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one m d a M f ( I U2) times as well on the government course :H tire graded 100. The relative performance of tires depends upon the actual conditions of their use, however, and may depart significantly from the norm t rc to variations in driving habits, service practices Er and differences in road characteristics and climate. heat and its ability to dissipate heat when tested under controlled csndidsns on a specified indoor laboratory test wheel. Sustained high temperature can cause the material of the tire to degenerate and reduce tire life, and excessive ternperaFure can lead to sudden fire faifwe. The grade C corresponds to a level of pedomance which ail passenger c x tires must meet e~nder the Federal Motor Vehicle Safety Stmda-d No. i09. Grades B asci A represent higher levels of perhmance an the laboratory test wheel than the minimum required by law. 'The traction grades, from highest to !owest, are A, 3, and C, and they represent the tire's ability to stop ora wet pavement as measured mder controlled conditions on specified government test surfaces of asphalt 2nd concrete. A tire marked &: may have poor traction performance. Warning: The traction grade assigned to this tire is based on braking (straight alead) traction tests and does not ifgcllude cornering (turning) traction. The wheels OR your vehicle were aligned and balanced careEulIy at the factory to give you the longest tire life acd best overall performance. Scheduled wheel alignment and wheel balancing are not needed. However, if you notice unusual tire wear or your vehicle pulling G R way OF the other, the akignment ~ may need to be reset. If YOU notice your vehicle vibrating when driving on a smooth road, your wheels may need to be rebalaaaced.