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, 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
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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2. Remove the nut that holds down the spare tire. See
Compact Spare Tire on page 5-83.
3. Remove the spare tire by placing your hands at the
four and eight o’clock positions. Gently pull it up
and out of the trunk. For vehicles equipped with the
2.0L supercharged engine, complete Step 4 rst,
then Step 3.
4. Remove the wing nut that holds the jack and
remove the jack and wheel wrench.
The tools you’ll be using include the jack (A) and wheel
wrench (B).You will need to turn the plastic wheel nut
counterclockwise to loosen the wheel wrench from
the jack.
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Press the button and then pull on the end of the wheel
wrench to extend the handle.
Removing the Flat Tire and
Installing the Spare Tire
1. If your vehicle is equipped with plastic wheel
covers, use the wheel wrench to loosen the plastic
wheel nut caps.
Once you have loosened the plastic wheel nut caps
with the wheel wrench, you can nish loosening
them with your ngers. The plastic nut caps do not
come off. Using the at end of the wheel wrench,
pry along the edge of the wheel cover until it
comes off.
If your vehicle has aluminum wheels, rst remove
the center cap by pulling it out with the wheel
wrench.
2. Use the wheel wrench to loosen all the wheel nuts.
Do not remove them yet.
Notice:Make sure that the jack lift head is in the
correct position or you may damage your vehicle.
The repairs would not be covered by your warranty.
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