uuChecking and Maintaining TiresuDOT Tire Quality Grading (U.S. Vehicles)304MaintenanceThe traction grades, from highest to lowest, are AA, A, B, and C.Those grades represent the tire’s ability to stop on wet pavementas measured under controlled conditions on specifiedgovernment test surfaces of asphalt and concrete. A tire markedC may have poor traction performance.The temperature grades are A (the highest), B, and C,representing the tire’s resistance to the generation of heat and itsability to dissipate heat when tested under controlled conditionson a specified indoor laboratory test wheel. Sustained hightemperature can cause the material of the tire to degenerate andreduce tire life, and excessive temperature can lead to sudden tirefailure. The grade C corresponds to a level of performance whichall passenger car tires must meet under the Federal Motor VehicleSafety Standard No. 109. Grades B and A represent higher levelsof performance on the laboratory test wheel than the minimumrequired by law.■ Traction■ Temperature1TractionWarning: The traction gradeassigned to this tire is based onstraight-ahead braking traction tests,and does not include acceleration,cornering, hydroplaning, or peaktraction characteristics.1TemperatureWarning: The temperature grade forthis tire is established for a tire that isproperly inflated and notoverloaded. Excessive speed,underinflation, or excessive loading,either separately or in combination,can cause heat buildup and possibletire failure.
