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.
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.
Warning:The traction grade assigned to this tire is
based on straight-ahead braking traction tests, and does
not include acceleration, cornering, hydroplaning, or
peak traction characteristics.
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Removing the Spare Tire and Tools
The equipment you will need is located in the trunk.
1. Open the trunk. SeeTrunk on page 2-13for more
information.
2. Remove the convenience net if the vehicle has one.
3. Lift the handle on the spare tire cover. The handle
may hook on the front edge of the trunk’s
weatherstrip to hold the cover out of the way.4. Turn the wing nut counterclockwise and remove it.
5. Remove the compact spare tire.
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Removing the Flat Tire and
Installing the Spare Tire
Your vehicle may have aluminum wheels with exposed
wheel nuts. Use the wheel wrench to loosen all the
wheel nuts. Do not remove them yet.
Or, your vehicle may have steel wheel covers.
To remove the steel wheel covers and wheel nut caps,
loosen the plastic nut caps with the wheel wrench in
a counterclockwise direction. If needed, you can nish
loosening them with your ngers. The plastic nut
caps will not come off.Use the at end of the wheel wrench and pry along the
edge of the cover until it comes off. The edge of the
wheel cover could be sharp, so do not try to remove it
with your bare hands. Do not drop the cover or lay
it face down, as it could become scratched or damaged.
Once you have removed the wheel cover, use the
following procedure to remove the at tire and install
the spare tire.
1. Turn the wheel
wrench once on each
wheel nut to loosen
them. Do not remove
them yet.
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