1995 Oldsmobile 88 Owner's Manual - Page 264

Treadwear The treadwear grade a comparative rating based is on the wear rateof the tire when tested under controlled conditions ona specified government test course. For example, a tire graded 150 would wear one anda half (1 1/2) times as well on the government courseaas tire graded 100. The relative performance tires depends of upon the actual conditions their use, however, and of may depart significantly from the norm duevariations to in driving habits, service practices and differences in road characteristics and climate. Uniform Tire Quality Grading The following information relates to the system developed by the UnitedStates National Highway Traffic Safety Administration which grades tires by treadwear, traction and temperature performance. (This applies only to vehicles sold the United States.) in Traction A, B, C The traction grades, from highest to lowest are: B, A, and C. They represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces asphalt and of concrete. A tire marked C may have poor traction performance. Warning: The traction grade assigned to tire is based this on braking (straight-ahead) traction tests does not and include cornering (turning) traction. - 6-40