303uuChecking and Maintaining TiresuDOT Tire Quality Grading (U.S. Vehicles)ContinuedMaintenanceDOT Tire Quality Grading (U.S. Vehicles)The tires on your vehicle meet all U.S. Federal SafetyRequirements. All tires are also graded for treadwear, traction,and temperature performance according to Department ofTransportation (DOT) standards. The following explains thesegradings.Quality grades can be found where applicable on the tire sidewallbetween tread shoulder and maximum section width.The treadwear grade is a comparative rating based on the wearrate of the tire when tested under controlled conditions on aspecified government test course. For example, a tire graded 150would wear one and one-half (1 1/2) times as well on thegovernment course as a tire graded 100. The relative performanceof tires depends upon the actual conditions of their use, however,and may depart significantly from the norm due to variations indriving habits, service practices and differences in roadcharacteristics and climate.■ Uniform Tire Quality Grading■ Treadwear1Uniform Tire Quality GradingFor example:Treadwear 200Traction AATemperature AAll passenger car tires must conformto Federal Safety Requirements inaddition to these grades.
