For 1990-2009 cars

A Tire Performance Criteria (TPC) specifications number is molded in the sidewall near the size of all original equipment tires. This number assures that the tire meets GM performance standards for traction, endurance, dimensions, noise, handling, rolling resistance, etc. Usually, a specific TPC number is assigned to each tire size.

Replacement tires should be of the same size, load range, speed rating and construction as the original tires. This means that replacement tires should have the same TPC specification number. Tires of any other size or construction may seriously affect ride, handling, speedometer/odometer calibration, vehicle ground clearance, and tire clearance to the body and chassis. (This does not apply to the factory-furnished spare). Although the tread might differ, tires of different manufacturers that have the same TPC specification may be intermixed on the same vehicle.

New tires should be installed in pairs on the same axle. If only a single new tire is to be installed, it should be paired with the tire having the most tread to equalize braking traction.