1995 Pontiac Sunfire Owner's Manual - Page 243

Treadwear The treadwear grade is comparative rating based on a the wear rate of 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 course as a tire graded 100. The relative performance of tires depends upon the actual conditionsof their use, however, and may depart significantly from norm due to variations the in driving habits, service practices and differences in road characteristicsand climate. Traction A, B, C - Uniform Tire Quality Grading The following information relates to the system developed by the United States National Highway Traffic Safety Administration which grades tires by treadwear, traction and temperature performance. (This applies only to vehicles soldin the United States.) The traction grades, from highest tolowest are: A, B, and C. They represent the tire's ability to stop onwet pavement asmeasured under controlled conditions on specified governmenttest surfaces of asphalt and concrete. A tire marked 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. 6-38