Department Of Transportation Uniform Tire Quality Grades - RAM promaster 2017 User Manual

M A I N T A I N I N G Y O U R V E H I C L E

DEPARTMENT OF TRANSPORTATION UNIFORM TIRE QUALITY GRADES

The following tire grading categories were established by the National Highway
Traffic Safety Administration. The specific grade rating assigned by the tire's
manufacturer in each category is shown on the sidewall of the tires on your vehicle.
All passenger vehicle tires must conform to Federal safety requirements in addition
to these grades.
Treadwear
The Treadwear grade is a comparative rating, based on 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 and one-half 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.
Traction Grades
The Traction grades, from highest to lowest, are AA, A, B, and C. These 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.
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 Grades
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, when 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 vehicle tires must meet under the Federal Motor
Vehicle Safety Standard No. 109. Grades B and A represent higher levels of perfor-
mance on the laboratory test wheel, than the minimum required by law.
The temperature grade for this tire is established for a tire that is properly inflated
and not overloaded. Excessive speed, under-inflation, or excessive loading, either
separately or in combination, can cause heat buildup and possible tire failure.
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