(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 De nitions
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 In ation 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.
SeeIn ation - Tire Pressure on page 5-62.
5-58
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.
5-61
The valve stems on your extended mobility tires have
sensors that are part of the Tire Pressure Monitor
(TPM). SeeTire Pressure Monitor Operation
(Except Z06) on page 5-64. The TPM sensors contain
batteries which are designed to last for 10 years
under normal driving conditions. See your dealer if you
ever need to have a wheel replaced, or if the sensors
ever need replacement.
Notice:Using liquid sealants can damage the tire
valves and tire pressure monitor sensors in your
extended mobility tires. This damage would not be
covered by warranty. Don’t use liquid sealants
in your extended mobility tires.
If you feel that winter tires are needed for your driving
conditions, Goodyear Eagle M+S EMT tires are available
in your original equipment sizes from an authorized
Goodyear EMT retailer. These tires will improve snow
traction while maintaining your vehicle’s extended
mobility feature. When using winter tires on your vehicle,
be sure to use them on all four wheels. SeeBuying
New Tires on page 5-66.In ation - Tire Pressure
The tire and loading information label, 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). See
Loading Your Vehicle on page 4-33, for the location
of your vehicle’s tire and loading information label.
Notice:Don’t let anyone tell you that underin ation
or overin ation is all right. It’s not. If your tires
don’t have enough air (underin ation), you can get
the following:
Too much exing
Too much heat
Tire overloading
Bad wear
Bad handling
Bad fuel economy
If your tires have too much air (overin ation), you
can get the following:
Unusual wear
Bad handling
Rough ride
Needless damage from road hazards
5-62
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
Exterior painted surfaces are subject to aging, weather
and chemical fallout that can take their toll over a
period of years. You can help to keep the paint finish
looking new by keeping your vehicle garaged or covered
whenever possible.
Cleaning Windshield and Wiper Blades
If the windshield is not clear after using the windshield
washer, or if the wiper blade chatters when running,
wax, sap or other material may be on the blade
or windshield.
Clean the outside of the windshield with a full-strength
glass cleaning liquid. The windshield is clean if beads do
not form when you rinse it with water.
If you use a glass treatment or conditioner containing
ethyl alcohol or ethyl sulfate on your glass, be sure
to remove the acrylic roof panel, if so equipped. These
products may damage the panel.
Grime from the windshield will stick to the wiper blades
and affect their performance. Clean the blade by
wiping vigorously with a cloth soaked in full-strength
windshield washer solvent. Then rinse the blade
with water.
Check the wiper blades and clean them as necessary;
replace blades that look worn.
Cleaning Removable Roof Panel
Special care is necessary when cleaning, removing
and/or storing the roof panel.
•Flush with water to remove dust and dirt, then dry
the panel.
•Clean the panel with GM Glass Cleaner. Leave the
cleaner on the panel for one minute, then wipe the
panel with a soft, lint-free cloth.
•Do not use abrasive cleaning materials
If water drops are frequently allowed to dry on roof
panel, impurities in the water will adhere to the
top. These impurities may etch or mar the finish. When
the panel gets wet, you should dry it off.
Notice:If you use a glass treatment and/or
conditioner that contains ethyl alcohol or ethyl
sulfate on the roof panel, you could damage
the panel. The repairs would not be covered by your
warranty. Only use a GM-approved glass cleaner
on the roof panel.
5-87
Finish Damage
Any stone chips, fractures or deep scratches in the
finish should be repaired right away.
Minor chips and scratches can be repaired with touch-up
materials avaliable from your dealer or other service
outlets. Larger areas of finish damage can be corrected
in your dealer’s body and paint shop.
Carbon Fiber Hood
(Z06 Commemorative Edition
Model Only)
The hood on the Z06 Commemorative Edition model is
made from an advanced carbon fiber composite.
Under certain lighting conditions, the carbon fiber has a
faint woven appearance and can be seen through
the paint, but not felt. It is most obvious when viewing
the reflection of an object in the surface of the hood. The
edges of the object in the reflection will appear slightly
jagged, due to the woven carbon fiber material. This
is normal. No special care is needed.
Magnesium Wheel Finish
Notice:Improper paint repair or re nishing can
cause corrosion damage to a magnesium wheel. See
your dealer if a magnesium wheel needs paint
repair or re nishing.
Underbody Maintenance
Chemicals used for ice and snow removal and dust
control can collect on the underbody. If these are not
removed, corrosion and rust can develop on the
underbody parts such as fuel lines, frame, floor pan and
exhaust system even though they have corrosion
protection.
At least every spring, flush these materials from the
underbody with plain water. Clean any areas where mud
and debris can collect. Dirt packed in close areas of
the frame should be loosened before being flushed.
Your dealer or an underbody car washing system can
do this for you.
Titanium Exhaust System
(Z06 Only)
Time and high performance driving conditions can
cause a color change in titanium exhaust system parts.
This is normal for a titanium surface.
5-89