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.
5-74
Removing the Spare Tire and Tools
A. Retaining Bracket
and Wing Nut
B. Tool Kit and
Jack Tools
C. Wing Nut Retaining
Wheel BlocksD. Wheel Blocks
E. Jack
F. KnobA. Knob
B. Removable Storage Tray
C. Retaining Hook
D. Retaining Bracket
and Wing Nut
E. Tool Kit and Jack ToolsF. Mounting Bracket
G. Wing Nut Retaining
Wheel Blocks
H. Wheel Blocks
I. Jack Regular Models - Rear Access PanelExtended Models
5-80
On the regular models, the equipment is located on the
driver’s side of the vehicle, behind the left trim panel
in the rear of the vehicle. Unlatch the release lever
to open the trim panel door. Skip the rst step and follow
the last three.
On the extended models, the equipment you will need is
under the storage tray on the driver’s side of the
vehicle, in the trim panel.
1. Remove the tray to access the tools.
2. Remove the wing nut used to retain the tool kit by
turning it counterclockwise.
3. Turn the knob on the jack counterclockwise to
release the jack from its holder and to lower the
jack head.
4. Remove the wheel blocks and the wheel block
retainer by turning the wing nut counterclockwise.
You will use the jack handle extensions and the
wheel wrench to remove the underbody-mounted
spare tire.A. Spare Tire (Valve
Stem Pointed Down)
B. Hoist Assembly
C. Hoist Cable
D. Tire Retainer
E. Hoist Shaft
F. Hoist End of
Extension ToolG. Hoist Shaft
Access Hole
H. Wheel Wrench
I. Jack Handle
Extension
J. Spare Tire Lock
(If Equipped)
1. Open the spare tire lock cover on the bumper and
use the ignition key to remove the lock if your
vehicle is equipped with a spare tire lock (J).
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2. Assemble the wheel wrench (H) and the two jack
handle extensions (I) as shown.3. Insert the spare tire
end (open end) (F)
of the extension
through the hole (G)
in the rear bumper.
Be sure the hoist end of the extension connects to
the hoist shaft (E). The ribbed square end of the
extension is used to lower the spare tire.
4. Turn the wheel wrench (H) counterclockwise to
lower the spare tire to the ground. Continue to
turn the wheel wrench until the spare tire can be
pulled out from under the vehicle.
If the spare tire does not lower to the ground, the
secondary latch is engaged causing the tire
not to lower. SeeSecondary Latch System on
page 5-89.
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5. Use the wheel wrench
hook that allows you to
pull the hoist cable
towards you to assist
in reaching the
spare tire.
6. Tilt the retainer at the
end of the cable when
the tire has been
lowered, so it can be
pulled up through
the wheel opening.
7. Put the spare tire near the at tire.Removing the Flat Tire and
Installing the Spare Tire
Use the following pictures and instructions to remove
the at tire and raise the vehicle.
The tools you will be using include the jack (A), the
wheel blocks (B), the jack handle (C), the jack handle
extensions (D), and the wheel wrench (E).
5-83