Toyota Matrix 2004 Operating Manual page 188

Treadwear—The treadwear grade is
a comparative rating based on the
wear rate of the tire when tested un-
der controlled conditions on a speci-
fied government test course. For ex-
ample, a tire graded 150 would wear
one and a 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 hab-
its, service practices and differences
in road characteristics and climate.
188
'04 MATRIX_U (L/O 0307)
Traction AA, A, B, C—The traction
grades, from highest to lowest, are
AA, A, B, and C, and they 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 trac-
tion performance.
Warning: The traction grade assigned
to this tire is based on braking
(straight ahead) traction tests and
does not include cornering (turning)
traction.
Temperature A, B, C—The tempera-
ture grades are A (the highest), B,
and C, representing the tire's resis-
tance 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 cor-
responds 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 temperature grades for
this tire are established for a tire that
is properly inflated and not over-
loaded. Excessive speed, underinfla-
tion, or excessive loading, either sep-
arately or in combination, can cause
heat buildup and possible tire failure.
2004 COROLLA MATRIX from July. '03 Prod. (OM12814U)