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
Treadwear grade is a comparative rating based
on tire wear rate when tested under controlled
conditions on specified government test courses.
For example, a tire graded 150 would wear one
and a half (1-1/2) times as well on the govern-
ment course as a tire graded 100. However,
relative tire performance depends on actual driv-
ing conditions, and may vary significantly 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 your ve-
hicle tires is based on straight-ahead
braking traction tests and does not in-
clude acceleration, cornering, hydroplan-
ing or peak traction characteristics.
Temperature A, B and C
Temperature grades are A (the highest) , B, and
C. They represent a tire’s resistance to heat
build-up, and its ability to dissipate heat when
tested under controlled conditions on a specified
indoor laboratory test wheel. Sustained high tem-
perature can cause tire material to degenerate,
reducing tire life. Excessive temperatures can
lead to sudden tire failure. Grade C corresponds
to a performance level which all passenger car
tires must meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades A and B rep-
resent higher levels of performance on laboratory
test wheels 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 information9-25
ZREVIEW COPYÐ2006 Xterra(xtr)
Owners ManualÐUSA_English(nna)
08/01/05Ðdebbie
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