tires CHEVROLET ASTRO 2003 Owner's Manual

Brake Wear
Your vehicle has four-wheel disc brakes,
Disc brake pads have built-in wear indicators that make
a high-pitched warning sound when the brake
pads
are worn and new pads are needed. The sound
may come and go or be heard all the time your vehicle
is moving (except when you are pushing on the
brake pedal firmly).
The brake wear warning sound means that soon
your brakes won’t work well. That could lead to
an accident. When
you hear the brake wear
Notice: Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheei nuts are necessary to heip
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in
the proper sequence to
GM torque specifications.
Brake linings should always be replaced as complete
axle sets.
See
Brake System Inspection on page 6-31.
Brake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in
pedal travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you make a brake stop, your disc brakes
adjust for wear.
5-45

Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer.
If you ever have questions
about your tire warranty
and where to obtain service,
see your GMC Warranty booklet for details.
Poorl! lail -Jned anc. ..nproy-. ly used tires
are dangerous.
Overloading your tires can cause
overheating as a result of too much
friction. You could have an air-out and a
serious accident. See “Loading Your
Vehicle” in the Index.
CAUTION: (Continued)
0 Underinflated tires pose the same danger
as overloaded tires. The resulting accident
could cause serious injury. Check
all tires
frequently to maintain the recommended pressure. Tire pressure should be checked
when your tires are cold.
Overinflated tires are more likely to be
cut, punctured or broken by
a sudden
impact
- such as when you hit a pothole.
Keep tires at the recommended pressure.
Worn, old tires can cause accidents.
If your tread
is badly worn, or if your tires
have been damaged, replace them.
5-63

Inflation - Tire Pressure
The Certificationnire label, which is on the rear edge of
the driver’s door, shows the correct inflation pressures
for your tires when they’re cold. ‘Cold” means your
vehicle has been sitting for at least three hours or driven
no more than
1 mile (1.6 km).
Notice: Don’t let anyone tell you that underinflation
or overinflation is all right.
It’s not. If your tires
don’t have enough air (underinflation), you can get
the following:
Too much flexing
Too much heat
Tire overloading
Bad wear
Bad handling
Bad fuel economy
If your tires have too much air (overinflation),
you can get the following:
Unusual wear
Bad handling
0 Rough ride
Needless damage from road hazards
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.
Tire Inspection and Rotation
Tires should be rotated every 6,000 to 8,000 miles
(1 0 000 to 13 000 km).
Any time you notice unusual wear, rotate your tires
as soon as possible and check wheel alignment.
Also check for damaged tires or wheels. See
When It
Is Time for New Tires on page 5-66 and Wheel
Replacement on page
5-69 for more information.
5-64

Make sure the spare tire is stored securely. Push,
pull, and then try to rotate or turn the tire.
If it moves,
use the ratchevwheel wrench to tighten the cable.
See
Changing a Flat Tire on page 5-71.
The purpose Gf regular rotation is lo achieve more
uniform wear for all tires on the vehicle. The first rotation
is the most important. See “Part
A: Scheduled
Maintenance Services,” in Section
6, for scheduled
rotation intervals. After
the tires have been rotated, adjust the front and rear
inflation pressures as shown on the CertificationA-ire
label. Make certain that all wheel nuts are properly
tightened. See “Wheel Nut Torque” under
Capacities and
Specifications
on page 5-99.
When rotating your tires, always use the correct rotation
patterns shown here.
ts to
-
Rust or dirt on a wheel, or on the par
which
it is fastened, can make wheel nuts
become loose after a time. The wheel could
come
off and cause an accident. When you
change a wheel, remove any rust or dirt from
places where the wheel attaches to the vehicle.
In an emergency, you can use a cloth or a
paper towel to do
this; but be sure to use a
scraper
or wire brush later, if you need to,
to get all the rust or dirt
off. See “Changing a
Flat Tire” in the Index.
Don’t include the compact spare tire in your tire rotation.
5-65

When It Is Time for New Tires
One way to tell when it’s
time for new tires is to
check the treadwear
indicators, which will
appear when your tires
have only 1/16 inch
(1.6 mm) or less of
tread remaining. Some commercial truck
tires may not have
treadwear indicators.
You need a new tire
if any of the following statements
are true:
You can see the indicators at three or more places
You can see cord or fabric showing through the
The tread or sidewall is cracked, cut or snagged
The tire has a bump, bulge or split.
The tire has a puncture, cut or other damage that
around
the tire.
tire’s rubber.
deep enough to show cord or fabric.
can’t be repaired well because of the size or
location
of the damage.
Buying New Tires
To find out what kind and size of tires you need,
look at the Certification/Tire 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
“MS”
(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.
5-66

Mix---J tires could cause yo-. JO 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 temporarily,
it was developed
for use on your vehicle. See “Compact Spare
Tire” in the index.
If you use bias-ply tires on yo^. vet,,Je, 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.
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.
5-67

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
(1.5) 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 significantly from the norm
due to variations in driving habits, service practices
and differences in road characteristics and climate.
Temperature - A, B, C
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. 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 specified 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.
Warning: The temperature grade for this tire is
established for a tire that is properly inflated and
not overloaded. Excessive speed, underinflation, or
excessive loading, either separately or in combination,
can cause heat buildup and possible tire failure.
5-68

Wheel Alignment and Tire Balance If you need to replace any of your wheels, wheel bolts
or wheel nuts, replace them only with new
GM
The wheels on your vehicle were aligned and balanced original
equipment parts. This way, you will be sure to
carefully at the factory to give you the longest tire life have
the right wheel, wheel bolts and wheel nuts for
and best overall performance.
your
vehicle.
Scheduled wheel alignment and wheel balancing are
not needed. However,
if you notice unusual tire wear or
your vehicle pulling one way or the other, the alignment
may need to be reset.
If you notice your vehicle
vibrating when driving on a smooth road, your wheels
may need to be rebalanced.
Wheel Replacement
Replace any wheel that is bent, cracked or badly
rusted or corroded.
If wheel nuts keep coming loose,
the wheel, wheel bolts and wheel nuts should be
replaced. If the wheel leaks air, replace it (except some
aluminum wheels, which can sometimes be repaired).
See your dealer
if any of these conditions exist.
Your dealer will know the kind of wheel you need.
Each new wheel should have the same load-carrying
capacity, diameter, width, offset and be mounted
the same way as the one it replaces. the wrong replacement wheels, wheel
bolts or wheel nuts on your vehicle can be
dangerous.
It could affect the braking and
handling of your vehicle, make your tires lose
air and make you lose control. You could have
a collision
in which you or others could be
injured. Always use the correct wheel, wheel
bolts and wheel nuts for replacement.
Notice: The wrong wheel can also cause problems
with bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper height,
vehicle ground clearance and tire or tire chain clearance to the body and chassis.
See
Changing a Flat Tire on page 5-71 for more
information.
-~
5-69

Used Replacement Wheels
Putting a uscu 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
Notice: Use tire chains only where legal and only
when you must. Use only
SAE Class ”S” type chains
that are the proper size for your tires. Install them on the rear axle 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.
If a Tire Goes Flat
It’s unusual for a tire to “blow out” while you’re driving,
especially
if you maintain your tires properly. If air
goes out of a tire, it’s 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 flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
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’d use
in a skid. In any rear blowout, 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 flat, the next part shows how to use your
jacking equipment to change a flat tire safely.
5-70

Compact Spare Tire
Although the compact spare tire was fully inflated when
your vehicle was new, it can lose air after a time.
Check the inflation pressure regularly. It should be
60 psi (420 kPa).
After installing the compact spare on your vehicle,
you should stop as soon as possible and make sure
your spare tire is correctly inflated. The compact spare
is made to perform well at speeds up to
65 mph
(1 05 km/h) for distances up to 3,000 miles (5 000 km),
so you can finish your trip and have your full-size
tire repaired or replaced where you want.
Of course,
it’s best to replace your spare with a full-size tire as soon
as you can. Your spare will last longer and be in good
shape in case you need it again.
Notice: When the compact spare is installed, don’t
take your vehicle through an automatic car wash
with guide rails. The compact spare can get caught
on the rails. That can damage the tire and wheel,
and maybe other parts of your vehicle.
Don’t use your compact spare on other vehicles.
And don’t mix your compact spare tire or wheel with
other wheels or tires. They won’t fit. Keep your spare tire
and its wheel together.
Notice: Tire chains won’t fit your compact spare.
Using them can damage your vehicle and can
damage the chains too. Don’t use tire chains on
your compact spare.
5-82