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YARIS iA_OM_OM99N89z_(U)
7-6. Uniform Tire Quality Grading System (UTQGS)
7
Customer Information and Reporting Safety Defects
Uniform Tire Quality Grading System
(UTQGS)
This information relates to the tire grading system developed by the
U.S. National Highway Traffic Safety Administration for grading tires
by tread wear, traction, and temperature performance.
The tread wear 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-a-half 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
because of variations in driving habits, service practices and differ-
ences in road characteristics and climate.
The traction grades, from highest to lowest, are AA, A, B, and C.
These grades represent the tire’s ability to stop on wet pavement as
measured under controlled conditions on specified government test
surfaces of asphalt and concrete. A tire marked C may have poor
traction performance.
Tread Wear
Traction-AA, A, B, C
The traction grade assigned to this tire is based on braking (straight
ahead) traction tests and does not include acceleration cornering (turn-
ing), hydroplaning, or peak traction characteristics.
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