1997 Chevrolet Cavalier Owner's Manual - Page 287

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 sold in the United States.) The grades are molded on the sidewalls of most passenger car tires. The Uniform Tire Quality Grading system does not applyto deep tread, winter-type snow tires, space-saver or temporary usespare tires, tires with nominal rim diametersof 10 to 12inches (25 to 30 cm), or to some limited-production tires. While the tiresavailable on General Motors passenger cars and light trucks may vary with respect to these grades, they must also conform to Federal safety requirements and additional General Motors Tire Performance Criteria (TPC) standards. Treadwear The treadwear grade is a 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 tire a graded 100. The relative performance of tires depends upon the actual conditionsof their use, however, and may depart significantly from the norm to variations due in drivinghabits, service practices and differences in road characteristics and climate. Traction -- A, B, C The traction grades, from highest to lowest, are B, and A, C, and they represent the tire's ability to stop on wet 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 assignedto this tire is based on braking (straightahead) traction tests and does not include cornering (turning) traction. - 6-45