1998 Buick Skylark Owner's Manual - Page 266

Uniform Tire Quality Grading I Mixing tirescould cause you to lose control while driving. I you mix tires of different sizes or types f (radial andbias-belted tires), the vehicle may not handle properly, and could have a crash. you Using tires of different sizes may also cause damage to your vehicle. Be sure touse the same size and type tires all wheels. on It's all right to drive your compact spare, with though. It was developed for use on yourvehicle. I The following information relates to system the developed by the United States National Highway Traffic Safety Administration, which grades tires by treadwear, traction and temperature performance. (This in applies only to vehicles sold the United States.)The of grades are molded on the sidewallsmost passenger car tires.The Uniform Tire Quality Grading system does not applyto deep tread, winter-type snow tires, space-saver or temporary use spare tires, tires with nominal rim diametersof 10 to 12 inches (25 to 30 cm), or to some limited-production tires. While the tires available on General Motors passenger cars andlight trucks may vary with respect to these grades, they mustalso conform to Federal safety requirements and additional General Motors Tire Performance Criteria (TPC) standards. If you use bias-ply tires on your vehicle, the wheel rim flanges could develop cracks after many miles of driving. A tire and/orwheel could fail suddenly, causing crash.Use only radial-ply a tires with the wheels on your vehicle. 6-43