Mitsubishi MOTORS MIRAGE G4 2022 Owner's Manual page 239

Tires
Treadwear, Traction and Temper-
ature 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-
1
half (1 / ) times as well on the gov-
2
9
ernment 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
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
9-16 Vehicle care and maintenance
under controlled conditions on speci-
fied government test surfaces of
asphalt and concrete. A tire marked
C may have poor traction perfor-
mance.
Temperature
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 condi-
tions on a specified indoor laboratory
test wheel. Sustained high tempera-
ture 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 Vehi-
cle Safety Standard No. 109. Grades
B and A represent higher levels of
performance on the laboratory test
wheel than the minimum required by
law.
Tire inflation pressures
Proper tire inflation pressure is
essential for the safe and satisfactory
operation of your vehicle. The wrong
tire pressure will cause problems in
three major areas:
Safety

Too little pressure increases flex-
ing in the tire and can cause tire
failure. Too much pressure can
cause a tire to lose its ability to
cushion shock. Objects on the
road and potholes could then
cause tire damage that may result
in tire failure.
Economy

The wrong tire pressure can cause
uneven wear patterns in the tire
tread. These abnormal wear pat-
terns will reduce the tread life, and
the tire will have to be replaced
sooner.
Too little pressure also makes it
harder for the tire to roll, and this
uses up more fuel.
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