1998 Oldsmobile Cutlass Owner's Manual - Page 259

Treadwear The treadwear grade isa comparative rating based on The following information relates to the system the wear rateof the tire when tested under controlled developed by the United States National Highway conditions on a specified government test course. For Traffic Safety Administration, which grades tires by example, a tire graded 150 would wear one and a half treadwear, traction and temperature performance.(This (1 1/2) times as well on the government course as a tire applies only to vehicles sold the United States.) The in graded100. The relative performance of tiresdepends grades are molded on the sidewalls most passenger of of car tires.The Uniform Tire Quality Grading system does upon the actual conditions their use, however, and may depart significantly from the o m due to variations n not apply to deep tread, winter-type snow tires, in driving habits, service practices and differences in space-saver or temporary use spare tires, tires with road characteristics and climate. nominal rim diameters 10 to 12 inches (25 to30 cm), of or to some limited-production tires. Traction A, B, C While the tires available on General Motors passenger The traction grades, fkom highest to lowest, are A, and B, cars and light trucks may vary with respect to these C, and they represent the tire's ability to stop on wet grades, they must also conform Federal safety to pavement as measured mder controlled conditions on requirements and additional General Motors Tire specified government test surfaces of asphalt and concret Pedomance Criteria ( P C ) standards. A tire markedC may have poor traction e r f o m c e . p Warning: The traction grade assigned to this is based tire on braking (straight ahead) traction tests and does not include cornering (turning) traction. Uniform Tire Quality Grading --