Owner`s manual
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
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 habits, service practices and differences
in
road characteristics and climate.
Traction
-
A,
B,
C
The traction grades, from highest to lowest are:
A,
B,
and
C.
They represent the tire’s ability to stop
on
wet
pavement
as
measured under controlled conditions on
specified government test surfices of asphalt and
concrete.
A
tire marked
C
may have poor traction
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,
R,
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 Mure.
The grade
C
corresponds 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
performance on the
laboratory test wheel than
the
minimum required by law.
Warning: The temperature grade for this tire is
established
for
a tire that is properly inflated and not
overloaded. Excessive speed, underinflation, or
excessive loading, either separately or
in
combination,
can cause heat buildup and possible tire failure.
These grades are molded
on
the sidewalls
of
passenger
car tires.
While the tires available
as
standard
or
optional
equipment on General Motors vehicles may vary with
respect to these grades,
all
such tires meet General
Motors performance standards and have been approved
for use on General Motors vehicles. All passenger type
(P
Metric) tires must conform
to
Federal safety
requirements
in
addition
to
these grades.
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