2003 CHEVROLET C/K Owners Manual

6-59 Inflation -- Tire Pressure
The GVW Rating label, which is on the driver's door,
shows the correct inflation pressures for your tires
when they're cold. ªColdº 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
NOTICE: (Continued)
NOTICE: (Continued)
If your tires have too much air (overinflation),
you can get the following:

Unusual wear

Bad handling

Rough ride

Needless damage from road hazards

6-60
When to Check
Check your tires once a month or more. Also, check the
tire pressure of the spare tire (if equipped).
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.
Rims and Wheels
Rims and wheels are stamped with a maximum load
and cold inflation rating. Be sure you don't exceed
these limits.
Dual Tire Operation
When the vehicle is new, check the wheel nut tightness
on all wheels with a torque wrench after your first
100 miles (160 km) and then 1,000 miles (1 600 km)
after that. Whenever a wheel, wheel bolt or wheel nut is
removed or serviced, repeat the 100 miles (160 km), and
then 1,000 mile (1 600 km) wheel nut tightness check.
See ªTightening the Wheel Nutsº later in this section
for proper torque values and wheel nut tightening
information.
CAUTION:
If you operate your vehicle with a tire that is
badly underinflated, the tire can overheat. An
overheated tire can lose air suddenly or catch
fire. You or others could be injured. Be sure all
tires (including the spare, if any) are properly
inflated.
See ªTiresº and ªInflation -- Tire Pressureº in the Index
for more information on proper tire inflation.

6-61 When It's Time for New Tires
Replace your tires when the tread depth is down to
1/8 of an inch (3.2 mm) for the front tires, or 1/16 of
an inch (1.6 mm) for a rear tire. Also, you need a new
tire if:

You can see cord or fabric showing through the
tire's rubber.

The tread or sidewall is cracked, cut or snagged deep
enough to show cord or fabric.

The tire has a bump, bulge or split.

The tire has a puncture, cut or other damage that
can't be repaired well because of the size or location
of the damage.CAUTION:
Mixing tires could cause you to lose control while
driving. If you mix tires of different types
-- like
radial and bias
-belted tires -- the vehicle may not
handle properly, and you could have a crash. Be
sure to use the same type of tires all around.
When you replace tires, make sure they are the same
size, load range, speed rating and construction type
(bias, bias
-belted or radial) as your original tires.

6-62 Wheel Alignment and Tire Balance
The wheels on your vehicle were aligned at the factory
to give you the longest tire life and best overall
performance.
Proper front wheel alignment must be maintained in
order to ensure efficient steering, good directional
stability, and prevent abnormal tire wear. If you notice
unusual tire wear or your vehicle is 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 balanced.
Tightening the Wheel Nuts
CAUTION:
Wheel nuts that are not tight can work loose. If
all the nuts on a wheel come off, the wheel can
come off the vehicle, causing a crash. All wheel
nuts must be properly tightened. Follow the rules
in this section to be sure they are.
This section lets you know how often to check the
tightness of the wheel nuts on your vehicle and how
tight they must be.
First, use these pictures to decide what kind of wheels
you have.

6-63
Hub-Piloted Type,
8
-HoleHub
-Piloted Type,
10
-Hole
Then, follow the steps below for the wheels you have.
CAUTION:
Never use oil or grease on studs or the threads of
the wheel nuts. If you do, the nuts might come
loose. Your wheel could fall off, causing a crash.
Hub-Piloted Wheels, 8-Hole or 10-Hole
The studs and nuts used with these wheels have
right
-hand threads.
1. With intermittent pilot pads, position a pad at
12 o'clock to center the wheel and reduce run
-out.
2. Put the tire and rim assembly on the axle hub. Install
the outer rear tire and rim assembly so that its valve
stem is exactly opposite the valve stem on the inner
tire and rim assembly.
3. Put on the wheel nuts.
4. Finger
-tighten the nuts.
5. Oil the surfaces between the nuts and washers.
Do not oil the studs or the threads of the nut.
6. Tighten the nuts to 400 lb
-ft (542 N´m) if an 8-hole
stud or 480 lb
-ft (650 N´m) if a 10-hole stud. Use the
following diagrams.

6-64
8-Hole
10-Hole (Front or
Inner Dual Wheel)10-Hole
(Outer Dual Wheel)
CAUTION:
If wheel studs are damaged, they can break. If all
the studs on a wheel broke, the wheel could come
off and cause a crash. If any stud is damaged
because of a loose
-running wheel, it could be that
all of the studs are damaged. To be sure, replace
all studs on the wheel. If the stud holes in a wheel
have become larger, the wheel could collapse in
operation. Replace any wheel if its stud holes
have become larger or distorted in any way.
Inspect hubs and hub piloted wheels for damage.
Because of loose running wheels, piloting pad
damage may occur and require replacement of
the entire hub, for proper centering of the wheels.
When replacing studs, hubs, nuts or wheels, be
sure to use GM original equipment parts.

6-65
CAUTION:
Rust or dirt on a wheel, or on the parts to which
it is fastened, can make the wheel nuts become
loose after a time. The wheel could come off and
cause a crash. When you change a wheel, remove
any rust or dirt from the places where the wheel
attaches to the vehicle. In an emergency, you can
use a cloth or 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.
How Often to Check
Wheel tightness is so important you should have a
technician check nut tightness on all wheels with a
torque wrench after your first 100 miles (160 km), and
then 1,000 miles (1 600 km) after that. Be sure to repeat
this service whenever you have a tire removed or
serviced. See ªMaintenance Scheduleº in the Index for
further information.

6-66 Wheel Replacement
Replace any wheel that is bent, cracked or badly rusted.
If wheel nuts keep coming loose, replace the wheel. If
the wheel leaks air, replace it.
Your dealer will know the kind of wheel you need.
CAUTION:
A leaking wheel could fail without warning. A
wheel designed for tubeless tires could be leaking
because it is damaged. Don't use an inner tube or
some other thing to try to stop the leaking. Get a
new wheel of the proper type.
CAUTION:
Without the correct wheel, you may not be able
to stop properly, and you could have other
problems like a tire air
-out. You could have a
collision. If you don't go to your dealer to get a
new wheel, be sure you get the correct one. Each
new wheel should match the original wheel in
load
-carrying capacity, inflation pressure
capacity, diameter, width, offset and mounting
configuration.
Using wheels and tires with higher load-carrying limits
than the original wheels and tires doesn't change the
GAWR or the GVWR of your vehicle.