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.Temperature – A, B, C
The temperature grades
are A (the highest), B, and C,
representing the tire’s resistance
to the generation of heat and
its ability to dissipate heat
when tested under controlled
conditions on a speci ed indoor
laboratory test wheel. Sustained
high temperature can cause
the material of the tire to
degenerate and reduce tire life,
and excessive temperature
can lead to sudden tire failure.
The grade C corresponds to
a level of performance which
all passenger car tires must
meet under the Federal Motor
Vehicle Safety Standard
No. 109. Grades B and A
represent higher levels of
performance on the laboratory
test wheel than the minimum
required by law. It should
be noted that the temperature
grade for this tire is established
for a tire that is properly
in ated and not overloaded.
Service and Appearance Care 5-53
If a Tire Goes Flat
It is unusual for a tire to blowout
while you are driving, especially if
you maintain the tires properly. See
Tires on page 5-36. If air goes out of
a tire, It is much more likely to leak
out slowly. But if you should ever
have a blowout, here are a few tips
about what to expect and what to do:
If a front tire fails, the at tire will
create a drag that pulls the vehicle
toward that side. Take your foot off
the accelerator pedal and grip the
steering wheel rmly. Steer to
maintain lane position, and then
gently brake to a stop well out of
the traffic lane.
A rear blowout, particularly on a
curve, acts much like a skid and may
require the same correction you
would use in a skid. In any rearblowout, remove your foot from the
accelerator pedal. Get the vehicle
under control by steering the way
you want the vehicle to go. It may be
very bumpy and noisy, but you can
still steer. Gently brake to a stop, well
off the road if possible.
If a tire goes at, avoid further tire
and wheel damage by driving slowly
to a level place and stopping.
1. Turn on the hazard warning
ashers. SeeHazard Warning
Flashers on page 3-5.
2. Park the vehicle. Set the parking
brake rmly and put the shift
lever in P (Park).
3. Turn off the engine.
4. Inspect the at tire.{CAUTION
Lifting a vehicle and getting under
it to do maintenance or repairs is
dangerous without the appropriate
safety equipment and training. If a
jack is provided with the vehicle, it
is designed only for changing a
at tire. If it is used for anything
else, you or others could be badly
injured or killed if the vehicle slips
off the jack. If a jack is provided
with the vehicle, only use it for
changing a at tire.
This vehicle may come with a jack
and spare tire or a tire sealant and
compressor kit. To use the jack and
spare tire, seeChanging a Flat Tire
on page 5-65. To use the tire sealant
and compressor kit, seeTire Sealant
and Compressor Kit on page 5-57.
5-56 Service and Appearance Care
Tire Sealant and
Compressor Kit
{CAUTION
Idling a vehicle in an enclosed
area with poor ventilation is
dangerous. Engine exhaust may
enter the vehicle. Engine exhaust
contains Carbon Monoxide (CO)
which cannot be seen or smelled.
It can cause unconsciousness
and even death. Never run the
engine in an enclosed area that
has no fresh air ventilation. For
more information, seeEngine
Exhaust on page 2-30.
{CAUTION
Over-in ating a tire could cause
the tire to rupture and you or
others could be injured. Be sure to
read and follow the tire sealant and
compressor kit instructions and
in ate the tire to its recommended
pressure. Do not exceed the
recommended pressure.
{CAUTION
Storing the tire sealant and
compressor kit or other equipment
in the passenger compartment
of the vehicle could cause injury.
In a sudden stop or collision, loose
equipment could strike someone.
Store the tire sealant and
compressor kit in its original
location.If this vehicle has a tire sealant and
compressor kit, there may not be a
spare tire, tire changing equipment,
and on some vehicles there may not
be a place to store a tire.
The tire sealant and compressor
can be used to temporarily seal
punctures up to
1 4inch (6 mm) in the
tread area of the tire. It can also be
used to in ate an under in ated tire.
If the tire has been separated from
the wheel, has damaged sidewalls,
or has a large puncture, the tire
is too severely damaged for the tire
sealant and compressor kit to be
effective. SeeRoadside Assistance
Program on page 7-6.
Read and follow all of the tire
sealant and compressor kit
instructions.
Service and Appearance Care 5-57
1. Open the storage compartment
door of the convenience center
that is nearest the liftgate and
remove the cap on the bottom of
the storage compartment.
2. Open the carpet cutout that is
located through the hole of the
storage compartment.
3. Attach the lug wrench into the
hoist shaft.
4. Turn the lug wrench
counterclockwise to lower
the spare tire to the ground.
Continue turning the wrench
until the spare tire can be pulled
out from under the vehicle.
5. Tilt the retainer and slip it through
the wheel opening to remove the
spare tire from the cable.6. Turn the wrench clockwise to
raise the cable back up after
removing the spare tire.
Do not store a full-size or a at
road tire under the vehicle.
SeeStoring a Flat or Spare Tire
and Tools on page 5-74.
To continue changing the at tire,
seeRemoving the Flat Tire and
Installing the Spare Tire on
page 5-68.
If the spare tire will not lower, the
secondary latch could be engaged.
Service and Appearance Care 5-67