DEPARTMENT OF TRANSPORTATION UNIFORM TIRE
QUALITY GRADES
The following tire grading categories were established by the National High-
way 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 perfor-
mance of tires depends upon the actual conditions of their use, however,
and may depart significantly from the norm due to variations in driving hab-
its, 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
.
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 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 sud-
den tire failure
.
The grade C corresponds to a level of performance, which
MAINTAINING YOUR VEHICLE
150
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