tire size CHEVROLET ASTRO 2004 Owners Manual

The Tire and Loading Information label also tells you
the size and recommended in¯ation pressure for
the original equipment tires on your vehicle. For more
information on tires and in¯ation see
Tires on page 5-52andIn¯ation - Tire Pressure on page 5-61.
If your vehicle does not have the Tire and Loading
Information label, the Certi®cation/Tire label shows the
tire size and recommended in¯ation pressures
needed to obtain the Gross Vehicle Weight Rating
(GVWR) and the Gross Axle Weight Rating (GAWR) for
the front and rear axles. See ªCerti®cation/Tire Labelº
later in this section.
Steps for Determining Correct Load Limit
1. Locate the statement ªThe combined weight of
occupants and cargo should never exceed XXX
poundsº on your vehicle placard.
2. Determine the combined weight of the driver and
passengers that will be riding in your vehicle.
3. Subtract the combined weight of the driver and
passengers from XXX kilograms or XXX pounds.4. The resulting ®gure equals the available amount of
cargo and luggage load capacity. For example, if
the ªXXXº amount equals 1400 lbs. and there will be
®ve 150 lb. passengers in your vehicle, the
amount of available cargo and luggage load
capacity is 650 lbs. (1400-750 (5 x 150) =
650 lbs.).
5. Determine the combined weight of luggage and
cargo being loaded on the vehicle. That weight
may not safely exceed the available cargo
and luggage load capacity calculated in Step 4.
6. If your vehicle will be towing a trailer, the load from
your trailer will be transferred to your vehicle.
Consult this manual to determine how this reduces
the available cargo and luggage load capacity of
your vehicle. See
Towing a Trailer on page 4-35for
important information on towing a trailer, towing
safety rules and trailering tips.
4-31

Loading Your Vehicle
Item Description Total
AVehicle Capacity Weight
for Example 3=1,000 lbs
(453 kg)
BSubtract Occupant
Weight 200 lbs
(91 kg)´5=1000 lbs (453 kg)
CAvailable Cargo
Weight=0 lbs. (0 kg)
Refer to your vehicle's tire and loading information label
for speci®c information about your vehicle's capacity
weight and seating positions. The combined weight of
the driver, passengers and cargo should never
exceed your vehicle's capacity weight.
Certi®cation/Tire Label
The Certi®cation/Tire label in your vehicle will look
similar to this example.
The Certi®cation/Tire label is found on the rear edge of
the driver's door. The label shows the size of your
original tires and the in¯ation pressures needed to obtain
the gross weight capacity of your vehicle.
This is called the Gross Vehicle Weight Rating (GVWR).
The GVWR includes the weight of the vehicle, all
occupants, fuel, cargo and tongue weight, if pulling a
trailer. Example 3
4-33

(A) Tire Size Code:The tire size code is a combination
of letters and numbers used to de®ne a particular
tire's width, height, aspect ratio, construction type and
service description. See the ªTire Size Codeº illustration
later in this section for more detail.
(B) Tire Performance Criteria Speci®cation (TPC
Spec):Original equipment tires designed to GM's
speci®c tire performance criteria have a TPC
speci®cation code molded onto the sidewall. GM's TPC
speci®cations 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 Identi®cation Number (TIN):The letters and
numbers following DOT code are the Tire Identi®cation
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.
(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 5-71.
(G) Maximum Cold In¯ation Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For information on
recommended tire pressure see
In¯ation - Tire Pressure
on page 5-66andLoading Your Vehicle on page 4-30.
5-58

(A) Tire Size:The tire size code is a combination of
letters and numbers used to de®ne a particular
tire's width, height, aspect ratio, construction type and
service description. See the ªTire Sizeº illustration
later in this section for more detail.
(B) Tire Performance Criteria Speci®cation (TPC
Spec):Original equipment tires designed to GM's
speci®c tire performance criteria have a TPC
speci®cation code molded onto the sidewall. GM's TPC
speci®cations meet or exceed all federal safety
guidelines.
(C) Dual Tire Maximum Load:Maximum load that can
be carried and the maximum pressure needed to
support that load when used in a dual con®guration. For
information on recommended tire pressure see
In¯ation - Tire Pressure on page 5-66andLoading Your
Vehicle on page 4-30.
LT-Metric Tire
5-59

(D) 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.
(E) Tire Identi®cation Number (TIN):The letters and
numbers following DOT code are the Tire Identi®cation
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.
(F) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(G) Single Tire Maximum Load:Maximum load that
can be carried and the maximum pressure needed
to support that load when used as a single. For
information on recommended tire pressure see
In¯ation
- Tire Pressure on page 5-66andLoading Your
Vehicle on page 4-30.
Compact Spare Tire Example
5-60

(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 ¯at. See
Compact Spare Tire on
page 5-86andIf a Tire Goes Flat on page 5-74.
(B) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(C) Tire Identi®cation Number (TIN):The Tire
Identi®cation 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 In¯ation Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. See
Compact Spare Tire
on page 5-86andLoading Your Vehicle on page 4-30.(E) Tire In¯ation:The temporary use tire or compact
spare tire should be in¯ated to 60 psi (420 kPa).
For more information on tire pressure and in¯ation see
In¯ation - Tire Pressure on page 5-66.
(F) Tire Size:A combination of letters and numbers
de®ne a tire's width, height, aspect ratio, construction
type and service description. The letter ªTº as the
®rst character in the tire size means the tire is for
temporary use only.
(G) Tire Performance Criteria Speci®cation (TPC
Spec):Original equipment tires designed to GM's
speci®c tire performance criteria have a TPC
speci®cation code molded onto the sidewall. GM's TPC
speci®cations meet or exceed all federal safety
guidelines.
5-61

Tire Size
The following examples show the different parts of a
tire size.
(A) Passenger (P-Metric) Tire:The United States
version of a metric tire sizing system. The letter ªPº as
the ®rst character in the tire size means a passenger
vehicle tire engineered to standards set by the U.S. Tire
and Rim Association.(B) Tire Width:The three-digit number indicates the
tire section width in millimeters from sidewall to sidewall.
(C) Aspect Ratio:A two-digit number that indicates
the tire height-to-width measurements. For example, if
the tire size aspect ratio is ª75,º as shown in item ªCº of
the illustration, it would mean that the tire's sidewall is
75% 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
ªRº means radial ply construction; the letter ªDº means
diagonal or bias ply construction; and the letter ªBº
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a tire. The
load index can range from 1 to 279. Speed ratings
range from ªAº to ªZº. Passenger (P-Metric) Tire
5-62

(A) Light Truck (LT-Metric) Tire:The United States
version of a metric tire sizing system. The letter ªLTº as
the ®rst two characters in the tire size means a light
truck tire engineered to standards set by the U. S. Tire
and Rim Association.
(B) Tire Width:The three-digit number indicates the
tire section width in millimeters from sidewall to sidewall.
(C) Aspect Ratio:A two-digit number that indicates
the tire height-to-width measurements. For example, if
the tire size aspect ratio is ª75,º as shown in item ªCº of
the illustration, it would mean that the tire's sidewall is
75% 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
ªRº means radial ply construction; the letter ªDº means
diagonal or bias ply construction; and the letter ªBº
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a tire. The
load index can range from 1 to 279. Speed ratings
range from ªAº to ªZº. The light truck tire size example
above shows dual or single tire con®gurations.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. Light Truck (LT-Metric) Tire
5-63

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. See
Uniform Tire Quality
Grading on page 5-71.
Vehicle Capacity Weight:The number of designated
seating positions multiplied by 150 lbs. (68 kg) plus
the rated cargo load. See
Loading Your Vehicle
on page 4-30.
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 in¯ation pressure. See
Loading Your
Vehicle on page 4-30.
In¯ation - Tire Pressure
The Certi®cation/Tire label or Tire and Loading
Information label shows the correct in¯ation 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). See
Loading Your
Vehicle on page 4-30.
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
5-66

{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 ªChanging a Flat
Tireº in the Index.
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. Some
commercial truck tires may
not have treadwear
indicators.
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.
5-69