Maintenance 197
INFORMATION ABOUT UNIFORM TIRE
QUALITY GRADING
Tire Quality Grades apply to new pneumatic passenger car
tires. The quality grades can be found where applicable on the
tire sidewall between tread shoulder and maximum section
width. A sample tire quality grade would be: Treadwear 200
Traction AA Temperature A
These Tire Quality Grades are determined by standards that
the United States Department of Transportation has set.
Tire Quality Grades apply to new pneumatic passenger car
tires. They do not apply to deep tread, winter-type snow tires,
temporary use spare tires, light truck or "LT" type tires, tires
with nominal rim diameters of 10 to 12 inches or limited pro-
duction tires as defined in Title 49 Code of Federal Regula-
tions Part 575.104(c)(2).
U.S. Department of Transportation - Tire
Quality Grades
The U.S. Department of Transportation requires Mobility Ven-
tures to give you the following information about tire 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 (1 1/2) 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 habits, service practices, and dif-
ferences in road characteristics and climate.
Traction Grades (AA, A, B, C)
The traction grades, from highest to lowest are AA, A, B and
C. The grades represent the tire's ability to stop on wet pave-
ment as measured under controlled conditions on specified
government test surfaces of asphalt and concrete. A tire
marked C may have poor traction performance.
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 (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 dissi-
pate heat when tested under controlled conditions on a specified
indoor laboratory test wheel. Sustained high temperature can
cause the material of the tire to degeneration and reduce tire life.
Excessive temperature can lead to sudden tire failure. The grade C
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