2004 CHEVROLET CORVETTE Owners Manual

When to Check
Check your tires once a month or more.
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 are underinflated.
Remove the valve cap from the tire valve stem. Press
the tire gage firmly onto the valve to get a pressure
measurement. If the cold tire inflation pressure matches
the recommended pressure on the tire and loading
information label, no further adjustment is necessary. If
the inflation pressure is low, add air until you reach
the recommended amount.
If you overfill the tire, release air by pushing on the
metal stem in the center of the tire valve. Recheck the
tire pressure with the tire gage.Be sure to put the valve caps back on the valve stems.
They help prevent leaks by keeping out dirt and
moisture.
If your vehicle is equipped with the Tire Pressure
Monitor, you can check tire inflation pressures while
driving. After you’ve reached a speed of 15 mph
(24 kmh) or more, press and release the GAGES button
on the Driver Information Center (DIC) until the front
tire pressures are displayed. Then, press and release
the GAGES button for the rear tire pressures. If the
display doesn’t show tire pressure, or if the SERVICE
TIRE MON SYS message appears see your dealer
for service. For more information, seeTire Pressure
Monitor Operation (Except Z06) on page 5-64andDriver
Information Center (DIC) on page 3-48.
5-63

Tire Pressure Monitor Operation
(Except Z06)
The Tire Pressure Monitor (TPM) has a sensor on each
road wheel that transmits to a receiver on the
instrument panel.
The system operates on a radio frequency subject to
Federal Communications Commission (FCC) Rules and
with Industry and Science Canada.
This device complies with Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
(1) this device may not cause harmful interference, and
(2) this device must accept any interference received,
including interference that may cause undesired
operation.
This device complies with RSS–210 of Industry and
Science Canada. Operation is subject to the following
two conditions: (1) this device may not cause
interference, and (2) this device must accept any
interference received, including interference that may
cause undesired operation of the device.Changes or modifications to this system by other than
an authorized service facility could void authorization to
use this equipment.
If a tire’s inflation pressure is between 5 psi (35 kPa)
and 25 psi (170 kPa), you will see a message on
the Driver Information Center. This message will show
which tire is underinflated and two chimes will sound. An
example would be LOW TIRE PRESSURE-LR. This
would mean that the inflation pressure in your left rear
tire is between 5 psi (35 kPa) and 25 psi (170 kPa).
If the inflation pressure in the tire drops below
5 psi (35 kPa), the message would read FLAT TIRE-LR
and four chimes will sound. SeeDriver Information
Center (DIC) on page 3-48.
The TPM will also alert you if a tire’s pressure is higher
than 42 psi (290 kPa). The message will show which
tire is overinflated and two chimes will sound. An
example would be HIGH PRESSURE-LR. This would
mean that the inflation pressure in your left rear tire
is higher than 42 psi (290 kPa). SeeDriver Information
Center (DIC) on page 3-48.
5-64

If a tire pressure message appears on the Driver
Information Center, stop as soon as you can. Have the
tire pressures checked and set to those shown on
your Tire-Loading Information label. SeeInation - Tire
Pressure on page 5-62.
{CAUTION:
When the LOW TIRE PRESSURE or FLAT TIRE
message is displayed on the Driver Information
Center, your vehicle’s handling capabilities will
be reduced during severe maneuvers. If you
drive too fast, you could lose control of your
vehicle. You or others could be injured. Don’t
drive over 55 mph (90 km/h) when the LOW
TIRE PRESSURE or FLAT TIRE message is
displayed. Drive cautiously, and check your
tire pressures as soon as you can.
Tire Rotation
The tires on your vehicle are different sizes front to rear.
Due to this, your tires should not be rotated. Each tire
and wheel should be used only in the position it is in.
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.
You need a new tire if any of the following statements
are true:
•You can see the indicators at three or more places
around the tire.
•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.
5-65

Buying New Tires
To find out what kind and size of tires your vehicle
needs, look at the Tire and Loading Information label.
SeeLoading Your Vehicle on page 4-33, for an example
of the label and where it is located on your vehicle.
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,
GM recommends that you get tires with that same
TPC Spec number. That way your vehicle will continue
to have tires that are designed to give proper
endurance, handling, load range, speed rating, traction,
ride, tire pressure monitoring system performance
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.{CAUTION:
Mixing tires could cause you to lose control
while driving. If you mix tires of different sizes
(other than those originally installed on your
vehicle) or types (radial and bias-belted tires),
the vehicle may not handle properly, and you
could have a crash. Using tires of different
sizes (other than those originally installed on
your vehicle) may also cause damage to your
vehicle. Be sure to use the correct size and
type tires on all four wheels.
If your vehicle is equipped with Extended Mobility Tires
and you feel that winter tires are needed, see
Extended Mobility Tires (Except Z06) on page 5-61.
{CAUTION:
If you use bias-ply tires on your vehicle, the
wheel rim anges 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.
5-66

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 (1.5) 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.
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.
5-67

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 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.
Wheel Alignment and Tire Balance
The wheels on your vehicle were aligned and balanced
carefully at the factory to give you the longest tire life
and best overall performance.
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.
5-68

If you need to replace any of your wheels, wheel bolts
or wheel nuts, replace them only with new GM
original equipment parts. This way, you will be sure to
have the right wheel, wheel bolts and wheel nuts
for your vehicle.
{CAUTION:
Using 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 clearance to the
body and chassis.
{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make 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 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.
{CAUTION:
Never use oil or grease on studs or the
threads of the wheel nuts. If you do, the wheel
nuts might come loose and the wheel could
fall off, causing a crash.
5-69

{CAUTION:
Incorrect wheel nuts or improperly tightened
wheel nuts can cause the wheel to become
loose and even come off. This could lead to a
crash. Be sure to use the correct wheel nuts. If
you have to replace them, be sure to get new
GM original equipment wheel nuts.
Notice:Improperly tightened wheel nuts can lead
to brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper
torque specication.
Magnesium Wheels
Notice:If your vehicle has magnesium wheels,
moisture on or around the mounting surface of the
magnesium wheel will cause corrosion and
damage to the wheel. To help prevent this, a
magnesium wheel uses two rubber O-rings. One
goes on the inboard side of the wheel and the other
on the back of the center hubcap. When you put
a magnesium wheel back on, be sure the O-rings are
correctly installed. On the inboard side, of the
wheel, work the O-ring into the groove. When
properly installed, this O-ring ts snugly. The other
O-ring goes around the retaining legs of the
center cap.
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.
5-70