1996 Cadillac DeVille Owner's Manual - Page 301

A CAUTION: Mixing tires could cause youto lose control while driving. If you mix tires of different sizes or types (radial and bias-belted tires), the vehicle may not handle properly, and you could havea crash. Using tires of different sizes may also cause damage to your vehicle. Be sure to use the same size and type tires on all four wheels. It's allright to drive with your compact spare, though. It was developed for use on your vehicle. 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 and light trucks may with respect to these vary grades, they must also conform to Federal safety requirements and additional General Motors Tire Performance Criteria(TPC) standards. Treadwear The treadwear grade is a comparative rating on based the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one anda half (1 1/2) times as well on the government course as a tire graded 100. The relative performance tires depends of upon the actual conditions their use, however, of and may depart significantly from the norm due to variations in driving habits, service practices and differences in road characteristics and climate. 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 treadwear, traction and temperature performance. (This applies only to vehicles sold the United States.) The in grades are moldedon the sidewallsof most passenger car tires. The Uniform Tire Quality Grading system does not apply to deep tread, winter-type snow tires, space-saver or temporaryuse spare tires, tires with 6-40