Treadwear; Traction Grades; Traction Aa A B C; Temperature A B C - Ford 1999 Mustang Owner's Manual

Maintenance and care
about tire grades exactly as the government has
written it.

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
performance 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 differences 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 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 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 conditions on a
specified indoor laboratory test wheel. Sustained
high temperature 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 corresponds to a level of performance which
all passenger car tires must meet under the Federal
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