1998 Pontiac Grand Am Owner's Manual - Page 279

A CAUTION: Mixing tires could cause you to lose control while driving. If you mix tires of different sizesor types (radial and bias-belted tires), the vehicle not may handle properly, and you could have a crash. also Using tires of different sizes may cause damage toyour vehicle. Be sure to use the same size and typetires on all wheels. It's all right to drive with your compact spare, though. It was developedfor use on your vehicle. I Uniform Tire Quality Grading The following information relates the system to developed by the United States National Highway Traffic Safety Administration, which grades tires by (This treadwear, traction and temperature performance. applies only to vehicles soldin the United States.) The of grades are molded on the sidewallsmost passenger Tire car tires. The Uniform Quality Grading system does not applyto deep tread, winter-type snow tires, tires, space-saver or temporary use spare tires with of nominal rim diameters 10 to 12 inches (25 to 30 cm), or to some limited-production tires. While the tires available on General Motors passenger trucks may vary with respect these to cars and light grades, they must also conform Federal safety to requirements and additional General Motors Tire Performance Criteria (TPC) standards. 1 A CAUTION: If you use bias-plytires on your vehicle,the wheel rim flanges could develop cracks after many milesof driving. A tire and/or wheel could fail suddenly, causing crash. Use onlyradial-ply a tires with the wheels on your vehicle. 6-46