The Uniform Tire Quality Grading is a labeling system
required by the federal government. All tires sold in the United States must be
graded & labeled with information on treadwear, temperature (resistance to
heat buildup) & traction. These ratings are intended to help consumers more
easily compare tires. Tires sold in the United States must be examined through a
series of tests defined by the government & conducted by the manufacturer.
Manufacturers are then responsible for assigning ratings to their products.
The treadwear grade is based on a 7,200-mile wear test conducted under
controlled conditions on a standard test course. Tires are measured for wear,
& the life expectancy is extrapolated to wear-out, which is 2/32 inch of
tread. Tire manufacturers grade their tires based on this standard test. The
higher the grade, the longer the expected tire life. Treadwear gradings are
given in numbers. For example, a tire graded 300 would wear twice as long on the
standard test course as a tire graded 150. The relative performance of tires
depends upon the actual conditions of their use, however, & may depart
significantly from the norm due to differences in road characteristics &
Traction grades are A, B & C, with A being highest. The rating is based on a
low-speed (40 mph) wet braking test & generally indicates the traction
capability of the tread compound in straight-ahead braking. Due to the low speed
& relatively rough test surface, results are not greatly affected by tread
patterns. Also, the grade does not indicate the tire's relative ability to
generate cornering force or to resist hydroplaning.
The temperature grades are A (the highest), B, & C, & they represent the
tire's resistance to the generation of heat & 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 & reduce tire life. Excessive temperature can lead to sudden tire
failure. The grade C corresponds to a level of performance that all passenger
car tires must meet under the Federal Motor Vehicle Safety Standard No. 109.
Grades A & B represent higher levels of performance on the laboratory test
wheel than the minimum required by law.
temperature grade for each tire is established for a tire that is properly
inflated & loaded. Excessive speed, under inflation, excessive loading, either
separately or in combination, can cause heat buildup & possible tire failure.
grade designations are required by government regulations for comparison
purposes only. DUNLOP DISCLAIMS AND EXCLUDES FOR ALL PURPOSES ANY EXPRESS AND/OR
IMPLIED WARRANTY THAT IS CLAIMED IN WHOLE OR IN PART UPON THESE GRADE