Tire Quality Grading
Radial
tires
manufactured
after
Oct.
1,
1980
must
be graded and labeled in accordance
with
new Federal
regulations.
Standard
tests
are
conducted
to
measure
performance
In
the
areas
of
treadwear,
traction
and
temperature
resistance. Refer to the tire
sidewall
for the
specific
quality
grades
of
the
tires
provided on your
new
Saab.
Compact
spare tires are exempt.
TREADWEAR*
DOT QUALITY GRADES
TREADWEAR
TRACTION ABC
TEMPERATURE ABC
ALL
PASSENGER CAR TIRES MUST CONFORM TO FEDERAL
SAFETY
REQUIREMENTS IN ADDITION
TO
THESE GRADES.
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
%)
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
The traction grades, from highest to lowest, are
A,
B,
C,
and they 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. Warning: The traction grade assigned to this tire is based on braking (straightahead) traction tests and does not include
cornering (turning) traction.
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 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 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, underinfla-
tion, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure.
·On
July 8,1982, the National Highway Traffic Safety Administration proposed to suspend
this
grading requ irement while It undertakes a review
of
test
procedures.
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