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Uniform Tire Quality
Grading
Quality grades can be found
where applicable on the tire
sidewall between tread shoulder
and maximum section width.
For example:
Treadwear 200 Traction AA
Temperature A
The following information relates
to the system developed by the
United States National Highway
Traffic Safety Administration
(NHTSA), which grades tires
by treadwear, traction, and
temperature performance.
This applies only to vehicles
sold in the United States.The grades are molded on the
sidewalls of most passenger car
tires. The Uniform Tire Quality
Grading (UTQG) system does
not apply to deep tread,
winter-type snow tires,
space-saver, or temporary use
spare tires, tires with nominal rim
diameters of 10 to 12 inches
(25 to 30 cm), or to some
limited-production tires.
While the tires available on
General Motors passenger cars
and light trucks may vary with
respect to these grades, they
must also conform to federal
safety requirements and
additional General Motors Tire
Performance Criteria (TPC)
standards.Treadwear
The treadwear grade is a
comparative rating based on the
wear rate of the tire when tested
under controlled conditions on
a speci ed government test
course. For example, a tire
graded 150 would wear one
and a half (1.5) 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 signi cantly from the norm
due to variations in driving habits,
service practices, and differences
in road characteristics and
climate.
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Page 344 of 432

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 speci ed
government test surfaces of
asphalt and concrete. A tire
marked C may have poor traction
performance.
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 speci ed indoor
laboratory test wheel. Sustained
high temperature can cause thematerial 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.
It should be noted that the
temperature grade for this tire
is established for a tire that
is properly in ated and not
overloaded. Excessive speed,
underin ation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.Wheel Alignment and
Tire Balance
The tires and wheels on your vehicle
were aligned and balanced carefully
at the factory to give you the longest
tire life and best overall performance.
Adjustments to wheel alignment and
tire balancing will not be necessary
on a regular basis. However, if you
notice unusual tire wear or your
vehicle pulling to one side or the
other, the alignment might need to be
checked. If you notice your vehicle
vibrating when driving on a smooth
road, the tires and wheels might
need to be rebalanced. See your
dealer/retailer for proper diagnosis.
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Used Replacement Wheels
{CAUTION
Putting a used wheel on your
vehicle is dangerous. You cannot
know how it has been used or
how far it has been driven. It
could fail suddenly and cause a
crash. If you have to replace a
wheel, use a new Saturn original
equipment wheel.
Tire Chains
{CAUTION
Do not use tire chains. There is
not enough clearance. Tire chains
used on a vehicle without the
proper amount of clearance can
cause damage to the brakes,
suspension or other vehicle parts.
The area damaged by the tire
chains could cause you to lose
control of the vehicle and you or
others may be injured in a crash.
(Continued)
CAUTION (Continued)
Use another type of traction
device only if its manufacturer
recommends it for use on the
vehicle and tire size combination
and road conditions. Follow
that manufacturer’s instructions.
To help avoid damage to the
vehicle, drive slowly, readjust or
remove the device if it is contacting
the vehicle, and do not spin the
vehicle’s wheels. If you do nd
traction devices that will t, install
them on the front tires.
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