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7-30
INSPECTION AND MAINTENANCE
79K21-03E
Uniform Tire Quality Grading
The U.S. National Highway Traffic
Safety Administration has developed a
grading system for evaluating the per-
formance of passenger car tires. The
following information will help you
understand the grading system, which
applies to vehicles sold in the U.S.
Consult your SUZUKI dealer or tire
retailer for help in choosing the correct
replacement tires for your vehicle.
Quality grades can be found where
applicable on the tire sidewall between
tread shoulder and maximum section
width. For example:
Treadwear 200 Traction AA Tempera-
ture A
DOT Quality Grades
Treadwear
Traction AA A B C
Temperature A B C
All Passenger Car 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 con-
ditions 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 rela-
tive performance of tires depends
upon the actual conditions of their use,
however and may depart significantly
from the norm due to variations in driv-
ing habits, service practices and differ-
ences in road characteristics and
climate.
Traction – AA, A, B, 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 measured
under controlled conditions on speci-
fied government test surfaces of
asphalt and concrete. A tire marked C
may have poor traction performance.
Temperature – A, B, 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 condi-
tions on a specified indoor laboratory
test wheel. Sustained high tempera-
ture 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 corre-
sponds 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 per-
formance on the laboratory test wheel
than the minimum required by law.
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.
WARNING
The temperature grade for this
tire is established for a tire that is
properly inflated and not over-
loaded. Excessive speed, under-
inflation or excessive loading,
either separately or in combina-
tion, can cause heat buildup and
possible tire failure.
Tires: 6