DOT Tire Quality Grading (U.S. Vehicles)
The tires on your vehicle meet all U.S. Federal Safety Requirements. All tires are also graded for treadwear, traction, and temperature performance according to Department of Transportation (DOT) standards. The following explains these gradings.
Uniform Tire Quality Grading
Quality grades can be found where applicable on the tire sidewall between shoulder and maximum section width.
Treadwear
The treadwear grade is a comparative rating based on the wear rate of the tire tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one and one-half (1 1/2) times as well on the government course As a tire graded 100. The relative performance of tires depends upon the actual conditions of their use, however, 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
For example:
Treadwear 200
Traction AA
Temperature A
All passenger car tires must conform to Federal Safety Requirements in addition to these grades.
Traction
The traction grades, from highest to lowest, are AA, A, B, and C. Those grades represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance.
Traction
Warning: The traction grade assigned to this tire is based on straight-ahead braking traction tests, and does not include acceleration, cornering, hydroplaning, or peak traction characteristics.
Temperature
The temperature grades are A (the highest), B, and C, representing the tire' s resistance to the generation of heat and its ability to dissipate heat tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the material of the tire to degenerate and reduce tire life, and excessive temperature can lead to sudden tire failure. The grade C corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Vehicle Safety Standard No. 109. Grades B and A represent higher levels of performance on the laboratory test wheel than the minimum required by law.
Temperature
Warning: The temperature grade fo r this ries established for a tire that is properly inflated and not overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can casue heat buildup and possible tire failure.
See also:
Door Locks
Power Door Locks
To lock all doors and the tailgate, push the top of the master door lock switch
on either front door, pull the lock tab rearward on the driver’s door, or use the
key on the o ...
Compact Spare Tire
Use the compact spare tire as a temporary replacement only. Get your regular
tire repaired or replaced, and put it back on your vehicle as soon as you can.
Check the air pressure of the compact spa ...
Tires
To safely operate your vehicle, your tires must be the proper type and size,
in good condition with adequate tread, and correctly inflated.
The following pages give more detailed information on how ...