4-15
Loss of Control
Let's review what driving experts say about what
happens when the three control systems (brakes, steering
and acceleration) don't have enough friction where the
tires meet the road to do what the driver has asked.
In any emergency, don't give up. Keep trying to
steer and constantly seek an escape route or area of
less danger.
Skidding
In a skid, a driver can lose control of the vehicle.
Defensive drivers avoid most skids by taking reasonable
care suited to existing conditions, and by not ªoverdrivingº
those conditions. But skids are always possible.
The three types of skids correspond to your vehicle's
three control systems. In the braking skid, your wheels
aren't rolling. In the steering or cornering skid, too
much speed or steering in a curve causes tires to slip and
lose cornering force. And in the acceleration skid, too
much throttle causes the driving wheels to spin.A cornering skid is best handled by easing your foot off
the accelerator pedal.
If you have the traction control system, remember:
It helps avoid only the acceleration skid.
If you do not have traction control, or if the system is
off, then an acceleration skid is also best handled by
easing your foot off the accelerator pedal.
If your vehicle starts to slide, ease your foot off the
accelerator pedal and quickly steer the way you want the
vehicle to go. If you start steering quickly enough, your
vehicle may straighten out. Always be ready for a
second skid if it occurs.
If you have Stabilitrak
, you may see the STABILITY
SYSTEM ACTIVE message on the Driver Information
Center. See ªStability System Active Messageº in
the Index.
Of course, traction is reduced when water, snow, ice,
gravel or other material is on the road. For safety, you'll
want to slow down and adjust your driving to these
conditions. It is important to slow down on slippery
surfaces because stopping distance will be longer and
vehicle control more limited.
5-23 Removing Wheel Covers and Wheel
Nut Caps
If your vehicle has aluminum wheels and a center cover
hides the wheel nuts, remove the center cover by using
the flat end of the wrench to pry it off. Do not drop the
cover or lay it face down, as it could become scratched
or damaged. Do not use a hammer or mallet on this type
of cover.
Removing the Flat Tire and Installing the
Spare Tire
1. Use the wheel wrench to loosen the wheel nuts, but
don't remove them.
2. The jack has a bolt at the end. Attach the wheel
wrench to the bolt to create a jack handle.
6-48
When to Check
Check your tires once a month or more.
Don't forget your compact spare tire. It should be
at 60 psi (420 kPa).
How to Check
Use a good quality pocket
-type gage to check tire
pressure. You can't tell if your tires are properly inflated
simply by looking at them. Radial tires may look
properly inflated even when they're underinflated.
Be sure to put the valve caps back on the valve
stems. They help prevent leaks by keeping out
dirt and moisture.
Check Tire Pressure System
The check tire pressure system can alert you to a large
change in the pressure of one tire. The system won't
alert you before you drive that a tire is low or flat.
You must begin driving before the system will
work properly.The CHECK TIRE PRESSURE message will appear on
the Driver Information Center (DIC) or the system
monitor TIRE PRESS light will come on if pressure
difference (low pressure) is detected in one tire. The
check tire pressure system may not alert you if:
more than one tire is low,
the vehicle is moving faster than 65 mph (105 km/h),
the system is not yet calibrated,
the tire treadwear is uneven,
the compact spare tire is installed,
tire chains are being used, or
the vehicle is being driven on a rough or frozen road.
If the anti
-lock brake system warning light comes on,
the check tire pressure system may not be working
properly. See your dealer for service. Also, see
ªAnti
-Lock Brake System Warning Lightº in the Index.
The check tire pressure system detects differences in tire
rotation speeds that are caused by changes in tire
pressure. The system can alert you about a low
tire
-- but it doesn't replace normal tire maintenance.
See ªTiresº in the Index.
6-52 Buying New Tires
To find out what kind and size of tires you need, look at
the Tire
-Loading Information label.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specification (TPC Spec)
number on each tire's sidewall. When you get new tires,
get ones with that same TPC Spec number. That way
your vehicle will continue to have tires that are designed
to give proper endurance, handling, speed rating,
traction, ride and other things during normal service on
your vehicle. If your tires have an all
-season tread
design, the TPC number will be followed by an ªMSº
(for mud and snow).
If you ever replace your tires with those not having a
TPC Spec number, make sure they are the same size,
load range, speed rating and construction type
(bias, bias
-belted or radial) as your original tires.
CAUTION:
Mixing tires could cause you to lose control while
driving. If you mix tires of different sizes or types
(radial and bias
-belted tires), the vehicle may not
handle properly, and you could have a crash.
Using tires of different sizes may also cause
damage to your vehicle. Be sure to use the same
size and type tires on all wheels.
It's all right to drive with your compact spare,
though. It was developed for use on your vehicle.
CAUTION:
If you use bias-ply tires on your vehicle, the
wheel rim flanges could develop cracks after
many miles of driving. A tire and/or wheel could
fail suddenly, causing a crash. Use only radial
-ply
tires with the wheels on your vehicle.
6-53 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 specified government test course.
For example, a tire graded 150 would wear one and a
half (1 1/2) 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 significantly 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 specified 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.
6-56
Used Replacement Wheels
CAUTION:
Putting a used wheel on your vehicle is
dangerous. You can't know how it's been used or
how far it's been driven. It could fail suddenly
and cause a crash. If you have to replace a wheel,
use a new GM original equipment wheel.
Tire Chains
CAUTION:
If your vehicle has P235/55R17 size tires, don't
use tire chains, there's 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, readjust or remove the
device if it's contacting your vehicle, and don't
spin your wheels.
If you do find traction devices that will fit, install
them on the front tires.
6-57
NOTICE:
If your vehicle has a tire size other than
P235/55R17 size tires, use tire chains only where
legal and only when you must. Use only SAE
Class ªSº type chains that are the proper size for
your tires. Install them on the front tires and
tighten them as tightly as possible with the ends
securely fastened. Drive slowly and follow the
chain manufacturer's instructions. If you can
hear the chains contacting your vehicle, stop and
retighten them. If the contact continues,
slow down until it stops. Driving too fast or
spinning the wheels with chains on will damage
your vehicle.
Appearance Care
Remember, cleaning products can be hazardous. Some
are toxic. Others can burst into flame if you strike a
match or get them on a hot part of the vehicle. Some are
dangerous if you breathe their fumes in a closed space.
When you use anything from a container to clean your
vehicle, be sure to follow the manufacturer's warnings
and instructions. And always open your doors or
windows when you're cleaning the inside.
Never use these to clean your vehicle:
Gasoline
Benzene
Naphtha
Carbon Tetrachloride
Acetone
Paint Thinner
Turpentine
Lacquer Thinner
Nail Polish Remover
They can all be hazardous
-- some more than
others
-- and they can all damage your vehicle, too.