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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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
your vehicle and you or others may be injured
in a crash. Use another type of traction device
only if its manufacturer recommends it for use
on your vehicle and tire size combination and
road conditions. Follow that manufacturer’s
instructions. To help avoid damage to your
vehicle, drive slowly, re-adjust or remove
the device if it is contacting your vehicle,
and do not spin your wheels. If you do nd
traction devices that will t, install them on
the rear tires.
Lifting Your Vehicle
{CAUTION:
Lifting a vehicle can cause an injury. The
vehicle can slip off the jack and roll over you
or other people. You and they could be badly
injured. Find a level place to lift your vehicle.
To help prevent the vehicle from moving:
1. Set the parking brake rmly.
2. Put an automatic transmission shift lever
in PARK (P).
3. Turn off the engine.
To be even more certain the vehicle won’t
move, you can put blocks in front of and
behind the wheels.
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If a Tire Goes Flat
It is unusual for a tire to “blow out” while you are
driving, especially if you maintain your tires properly.
If air goes out of a tire, it is much more likely to leak
out slowly. SeeTires on page 6-50for additional
information.
Your vehicle, when new, had run- at tires. This type
of tire can operate effectively with no air pressure,
so you will not need to stop on the side of the road
to change a at tire. You can just keep on driving.
The shorter the distance you drive and the slower the
speed, the greater the chance that the run- at tire
will not have to be replaced. Run- at tires perform
so well without any air that a Tire Pressure Monitor
(TPM) is used to alert you if a tire has lost pressure.
SeeRun-Flat Tires on page 6-56andTire Pressure
Monitor System on page 6-59.{CAUTION:
When the TIRE FLAT MAX SPD 55, REDUCED
HNDLG message is displayed on the Driver
Information Center, your vehicle’s handling
capabilities will be reduced during severe
maneuvers. If you drive too fast, you could
lose control of your vehicle. You or others
could be injured. Don’t drive over 55 mph
(90 km/h) when the TIRE FLAT MAX SPD 55,
REDUCED HNDLG message is displayed.
Drive cautiously and check your tire pressures
as soon as you can.
If the TPM system detects a tire pressure below
5 psi (34 kPa), the TIRE FLAT MAX SPD 55, REDUCED
HNDLG warning message is displayed on the Driver
Information Center (DIC). SeeDIC Controls and
Displays on page 3-64andDIC Warnings and Messages
on page 3-67for information and details about the
DIC operation and displays.
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