1996 Oldsmobile 88 Owner's Manual - Page 272

Uniform Tire Quality Grading Mixing tires could cause you to lose control while driving. If you mixtires of diffetent sizes or types (radial andbias-belted tires),the vehicle may not handle properly, and you could have a crash. Using tires of different sizes may also cause damage to your vehicle. Be sure touse the same size and type tires on all wheels. It's all right to drive with your compact spare, though. It was developed for use on yourvehicle. 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 onlyto vehicles soldin the United States.) The grades are molded on the sidewallsmost passenger of car tires.The Uniform Tire Quality Grading system does not apply to deep tread, winter-type snow tires, space-saver or temporary use spare tires, tires with nominal rim diameters of 10 to 12 inches (25 to 30 cm), or to some limited-production tires. While the tires available 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. 6-40