tires CHEVROLET CLASSIC 2004 Owner's Manual

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 GM Warranty booklet for details. For additional
information refer to the tire manufacturer’s booklet
included with your vehicle’s Owner’s Manual.
{CAUTION:
Poorly maintained and improperly 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.
Underinated 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.
CAUTION: (Continued)
CAUTION: (Continued)

Overinated 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.
Tire Sidewall Labeling
Useful information about a tire is molded into its
sidewall. The examples below show a typical passenger
car tire and a compact spare tire sidewall.
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(A) Tire Size:The tire size code is a combination of
letters and numbers used to define a particular
tire’s width, height, aspect ratio, construction type and
service description. See the “Tire Size” illustration
later in this section for more detail.
(B) Tire Performance Criteria Specication (TPC
Spec):Original equipment tires designed to GM’s
specific tire performance criteria have a TPC
specification code molded onto the sidewall. GM’s TPC
specifications meet or exceed all federal safety
guidelines.
(C) Department of Transportation (DOT):The
Department of Transportation (DOT) code indicates that
the tire is in compliance with the U.S. Department of
Transportation Motor Vehicle Safety Standards.
(D) Tire Identication Number (TIN):The letters and
numbers following DOT code are the Tire Identification
Number (TIN). The TIN shows the manufacturer
and plant code, tire size, and date the tire was
manufactured. The TIN is molded onto both sides of the
tire, although only one side may have the date of
manufacture.
Passenger Car Tire Example
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(E) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(F) Uniform Tire Quality Grading (UTQG):Tire
manufacturers are required to grade tires based on three
performance factors: treadwear, traction and
temperature resistance. For more information see
Uniform Tire Quality Grading on page 5-63.
(G) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For more information on
recommended tire pressure seeInation - Tire Pressure
on page 5-59andLoading Your Vehicle on page 4-32.
Compact Spare Tire Example
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(A) Temporary Use Only:The compact spare tire or
temporary use tire has a tread life of approximately
3,000 miles (5 000 km) and should not be driven
at speeds over 65 mph (105 km/h). The compact spare
tire is for emergency use when a regular road tire
has lost air and gone flat. SeeCompact Spare Tire on
page 5-79andIf a Tire Goes Flat on page 5-67.
(B) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(C) Tire Identication Number (TIN):The Tire
Identification Number (TIN). The TIN shows the
manufacturer and plant code, tire size, and date the tire
was manufactured. The TIN is molded onto both
sides of the tire, although only one side may have the
date of manufacture.
(D) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. SeeCompact Spare Tire
on page 5-79andLoading Your Vehicle on page 4-32.(E) Tire Ination:The temporary use tire or compact
spare tire should be inflated to 60 psi (420 kPa).
For more information on tire pressure and inflation see
Ination - Tire Pressure on page 5-59.
(F) Tire Size:A combination of letters and numbers
define a tire’s width, height, aspect ratio, construction
type and service description. The letter “T” as the
first character in the tire size means the tire is for
temporary use only.
(G) Tire Performance Criteria Specication (TPC
Spec):Original equipment tires designed to GM’s
specific tire performance criteria have a TPC
specification code molded onto the sidewall. GM’s TPC
specifications meet or exceed all federal safety
guidelines.
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Tread:The portion of a tire that comes into contact
with the road.
Treadwear Indicators:Narrow bands, sometimes
called “wear bars,” that show across the tread of a tire
when only 2/32 inch of tread remains. SeeWhen It
Is Time for New Tires on page 5-62.
UTQGS:Uniform Tire Quality Grading Standards, a tire
information system that provides consumers with
ratings for a tire’s traction, temperature and treadwear.
Ratings are determined by tire manufacturers using
government testing procedures. The ratings are molded
into the sidewall of the tire. SeeUniform Tire Quality
Grading on page 5-63.
Vehicle Capacity Weight:The number of designated
seating positions multiplied by 150 lbs. (68 kg) plus
the rated cargo load. SeeLoading Your Vehicle
on page 4-32.
Vehicle Maximum Load on the Tire:Load on an
individual tire due to curb weight, accessory weight,
occupant weight and cargo weight.
Vehicle Placard:A label permanently attached to a
vehicle showing the original equipment tire size
and recommended inflation pressure. SeeLoading Your
Vehicle on page 4-32.Ination - 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 4-32, for the location
of your vehicle’s tire and loading information label.
Notice:Don’t let anyone tell you that underination
or overination is all right. It’s not. If your tires
don’t have enough air (underination), 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 (overination), you
can get the following:
Unusual wear
Bad handling
Rough ride
Needless damage from road hazards
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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. Check
the tire’s inflation pressure when the tires are cold.
Cold means your vehicle has been sitting for at least
three hours or driven no more than 1 mile (1.6 km).
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.
Tire Inspection and Rotation
Tires should be rotated every 5,000 to 8,000 miles
(8 000 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. SeeWhen It Is Time
for New Tires on page 5-62andWheel Replacement
on page 5-65for more information.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The first rotation
is the most important. SeePart A: Scheduled
Maintenance Services on page 6-4, for scheduled
rotation intervals.
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When rotating your tires, always use the correct rotation
pattern shown here.
Don’t include the compact spare tire in your tire rotation.
After the tires have been rotated, adjust the front and
rear inflation pressures as shown on the Tire and
Loading Information label.
Make certain that all wheel nuts are properly tightened.
See “Wheel Nut Torque” underCapacities and
Specications on page 5-95.
{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 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.
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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.
Buying New Tires
To find out what kind and size of tires you need, look at
the tire and loading information label. For an example
of this label and its location, seeLoading Your Vehicle
on page 4-32.
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,
load range, 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.
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{CAUTION:
Mixing tires could cause you to 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.
{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.
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.
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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.
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.
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