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 tools you will need are located under the
passenger’s seat.
For crew cab models, the jack and wheel blocks are
located under the driver’s side rear seat.For regular and extended
cab vehicles, the jack and
wheel blocks are located
under the cover at the
center of the vehicle
behind the front seats.
The vehicle will have a cover if it is an extended or
regular cab.
Crew Cab
Regular/Extended Cab
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You will use the jack handle extensions and the wheel
wrench to remove the underbody-mounted spare tire.
A. Jack Handle
Extensions
B. JackC. Extension Tool
D. Wheel Wrench
E. Wheel Blocks
1. Assemble the wheel wrench (D) and the jack
handle extensions (A) as shown below.2. Insert the hoist end (chiseled end) of the extension
tool (C) through the hole in the rear bumper and
into the funnel-shaped guide. The chiseled end of
the extension is used to lower the spare tire.
3. Turn the wheel wrench (D) 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 5-81.
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