DOT (Department of Transportation) Quality
Grades: All passenger car tires must conform to
federal safety requirements in addition to these
grades.
Quality grades can be found where applicable on
the tire sidewall between tread shoulder and
maximum section width. For example:
Treadwear 200 Traction AA Temperature A
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified gov-
ernment 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.
Traction AA, A, B and C
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 mea-
sured under controlled conditions on specified
government test surfaces of asphalt and con-
crete. 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 A, B and C
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 exces-
sive temperature can lead to sudden tire failure.
The grade C corresponds to a level of perfor-
mance which all passenger car tires must meet
under the Federal Motor Safety Standard No.
109. Grades B and A represent higher levels of
performance on the laboratory test wheel than
the minimum required by law.
WARNING
The temperature grade for this tire is es-
tablished for a tire that is properly inflated
and not overloaded. Excessive speed,
under-inflation, or excessive loading, ei-
ther separately or in combination, can
cause heat build-up and possible tire
failure.
UNIFORM TIRE QUALITY GRADING
Technical and consumer information9-29
ZREVIEW COPYÐ2009 Xterra(xtr)
Owners ManualÐUSA_English(nna)
05/21/08Ðdebbie
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