1993 Buick Century Owner's Manual - Page 257

I A CAUTION: * Treadwear The treadwear grade is a comparative rating based on the wear rate of the tire whentested under controlled conditions on a specified government test course. For example, a tire graded1 0 would wear one and a half 5 as (1%) times as well on the government course a tire graded 100. The relative performanceof tires depends upon the actual conditions their use, however, and may of depart significantly from the norm due to variations in driving habits, service practices and differences road in characteristics and climate. Mlxing tires could cause you to lose control while driving. If you mlxtires of different sizes or types (radial and bias-belted tires) the vehlcle may not handleproperly, and you could havea crash. Be sure to use the same size and type tires on all four wheels. It's all right to drive wlth your compact spare, though. It was developed far use on your vehicle. I 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 The following information relates to the system developed pavement as measured under controlled conditions on by the United States National Highway Traffic Safety specified government test surfaces of asphalt and Administration which grades tiresby treadwear, traction concrete. A tire marked C may have poor traction and temperature performance. (This applies only to performance. vehicles sold in the United States.) Warning: The traction grade assigned to this tire is based on braking (straight-ahead) traction tests and does not include cornering (turning) traction. Uniform Tire Quality Grading 255