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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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Page 251 of 328

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.
If a Tire Goes Flat
Your vehicle has a tire in ator kit. There is no spare
tire, no tire changing equipment, and no place to store
a tire.
It is unusual for a tire to blow out while you are driving,
especially if you maintain your tires properly. See
Tires on page 5-44. If air goes out of a tire, it is much
more likely to leak out slowly. But, if you should
ever have a blow out, 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 blow out, particularly on a curve, acts much like
a skid and may require the same correction you
would use in a skid. In any rear blow out, 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.
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Page 266 of 328

Convertible Top
The vehicle’s convertible top should be cleaned often.
However, high pressure car washes may cause water to
enter your vehicle.
When you hand wash the top, do it in partial shade.
Use a mild soap, lukewarm water and a soft sponge.
A chamois or cloth may leave lint on the top, and
a brush can chafe the threads in the top fabric. Do
not use detergents, harsh cleaners, solvents or
bleaching agents.
Wet the entire vehicle and wash the top evenly to avoid
spots or rings. Let the soap remain on the fabric for
a few minutes. When the top is really dirty, use a mild
foam-type cleaner. Thoroughly rinse the entire
vehicle, then let the top dry in direct sunlight.
To protect the convertible top:
After you wash the vehicle, make sure the top is
completely dry before you lower it.
Do not get any cleaner on the vehicle’s painted
nish; it could leave streaks.
If you decide to go through an automatic car wash,
ask the manager if the equipment could damage
your top.
Aluminum or Chrome-Plated Wheels
The vehicle may be equipped with either aluminum or
chrome-plated wheels.
Keep the wheels clean using a soft clean cloth with mild
soap and water. Rinse with clean water. After rinsing
thoroughly, dry with a soft clean towel. A wax may then
be applied.
Notice:If you use strong soaps, chemicals,
abrasive polishes, cleaners, brushes, or cleaners
that contain acid on aluminum or chrome-plated
wheels, you could damage the surface of the
wheel(s). The repairs would not be covered by your
warranty. Use only GM-approved cleaners on
aluminum or chrome-plated wheels.
The surface of these wheels is similar to the painted
surface of your vehicle. Do not use strong soaps,
chemicals, abrasive polishes, abrasive cleaners,
cleaners with acid, or abrasive cleaning brushes on
them because you could damage the surface. Do not
use chrome polish on aluminum wheels.
Notice:Using chrome polish on aluminum wheels
could damage the wheels. The repairs would not
be covered by your warranty. Use chrome polish on
chrome wheels only.
Use chrome polish only on chrome-plated wheels, but
avoid any painted surface of the wheel, and buff off
immediately after application.
5-74