2004 CHEVROLET CORVETTE service

(C) Aspect Ratio:A two-digit number that indicates the
tire height-to-width measurements. For example, if
the tire size aspect ratio is “70,” as shown in item “C” of
the illustration, it would mean that the tire’s sidewall
is 70% as high as it is wide.
(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire. The letter
“R” means radial ply construction; the letter “D” means
diagonal or bias ply construction; and the letter “B”
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:These characters represent
the load range and the speed rating of a tire. The
load range represents the load carrying capacity a tire is
certified to carry. The load index can range from 1 to
279. The speed rating is the maximum speed a tire
is certified to carry a load. Speed ratings range
from “A” to “Z”.Tire Terminology and Denitions
Air Pressure:The amount of air inside the tire pressing
outward on each square inch of the tire. Air pressure
is expressed in pounds per square inch (psi) or
kilopascal (kPa).
Accessory Weight:This means the combined weight
of optional accessories. Some examples of optional
accessories are, automatic transmission, power steering,
power brakes, power windows, power seats, and air
conditioning.
Aspect Ratio:The relationship of a tire’s height to its
width.
Belt:A rubber coated layer of cords that is located
between the plies and the tread. Cords may be made
from steel or other reinforcing materials.
Bead:The tire bead contains steel wires wrapped by
steel cords that hold the tire onto the rim.
Bias Ply Tire:A pneumatic tire in which the plies are
laid at alternate angles less than 90 degrees to the
centerline of the tread.
Cold Ination Pressure:The amount of air pressure
in a tire, measured in pounds per square inch (psi)
before a tire has built up heat from driving.
SeeInation - Tire Pressure on page 5-62.
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Extended Mobility Tires
(Except Z06)
Your vehicle, when new, had Goodyear Extended
Mobility Tires (EMT). There’s no spare tire, no tire
changing equipment and no place to store a tire in the
vehicle. Extended Mobility Tires perform so well
without any air that a Tire Pressure Monitor (TPM) is
used to alert you if a tire has lost pressure.
If a tire goes flat, you won’t need to stop on the side of
the road to change the tire. You can just keep on
driving. The shorter the distance you drive and the
slower the speed, the greater the chance that the tire will
not have to be replaced. If you drive on a deflated
EMT for 50 miles (80 km) or less and at speeds
of 55 mph (90 km/h) or less, there is a good chance that
the tire can be repaired. The tire can operate effectively
with no air pressure for up to 200 miles (320 km) at
speeds up to 55 mph (90 km/h), but the tire would then
have to be replaced. When a tire is filled with air, it
provides a cushion between the road and the wheel.
Because you won’t have this cushion when driving on a
deflated tire, try to avoid potholes that could damage
your wheel and require replacement of it.
Some road hazards can damage a tire beyond repair.
This damage could occur even before you’ve driven
on the tire in a deflated condition. When a tire has been
damaged, or if you’ve driven any distance on adeflated EMT, check with an authorized Goodyear EMT
Service Center to determine whether the tire can be
repaired or should be replaced. To maintain your
vehicle’s extended mobility feature, all replacement tires
must be Extended Mobility Tires. As soon as possible,
contact the nearest authorized GM or Goodyear
EMT servicing facility for inspection and repair or
replacement. To locate the nearest GM or Goodyear
EMT servicing facility, call Roadside Assistance.
For phone numbers and Roadside Assistance details
seeRoadside Assistance Program on page 7-6.
You may also contact Goodyear, for the nearest
authorized EMT servicing facility, by calling
1-800-789-9878.
{CAUTION:
Extended mobility tires are constructed
differently than other tires and could explode
during improper service. You or others could
be injured or killed if you attempt to repair,
replace, dismount, or mount a extended
mobility tire. Let only an authorized EMT
Service Center repair, replace, dismount and
mount extended mobility tires.
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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.
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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

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.
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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 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

{CAUTION:
Getting under a vehicle when it is jacked up is
dangerous. If the vehicle slips off the jack, you
could be badly injured or killed. Never get
under a vehicle when it is supported only
by a jack.
{CAUTION:
Raising your vehicle with the jack improperly
positioned can damage the vehicle and even
make the vehicle fall. To help avoid personal
injury and vehicle damage, be sure to place
the jack in the proper location before raising
the vehicle.If you ever use a jack to lift your Corvette, such as to
display it at a show, follow the instructions that
came with the jack, and be sure to use the correct lifting
points to avoid damaging your vehicle.
Notice:Lifting your vehicle improperly can damage
your vehicle and result in costly repairs not
covered by your warranty. To lift your vehicle
properly, follow the advice in this part.
To help prevent vehicle damage:
Be sure to place a block or pad between the
jack and the vehicle.
Make sure the jack you’re using spans at least
two crossmember ribs.
Lift only in the areas shown in the following
pictures.
For additional information, see your dealer and the
Chevrolet Corvette service manual.
5-72

Lifting From the Rear
The rear lifting point can be accessed from the rear of
the vehicle, on either the driver’s or passenger’s side.
1. Locate the lifting point to jack your vehicle according
to the illustration shown.
2. Be sure to place a block or pad between the jack
and the vehicle.
3. Lift the vehicle with the jack, making sure the jack
spans at least two of the crossmember ribs.
For more information, seeDoing Your Own Service
Work on page 5-4.
5-74