wheel size CHEVROLET ASTRO CARGO VAN 2004 2.G Owners Manual

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 “P”
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 “75,” as shown in item “C”
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 “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: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 “A” to “Z”. The light truck tire size example
above shows dual or single tire congurations. Passenger (P-Metric) Tire
5-66

(A) Light Truck (LT-Metric) Tire:The United States
version of a metric tire sizing system. The letter “LT”
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 “75,” as shown in item “C”
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
“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: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 “A” to “Z”. The light truck tire size example
above shows dual or single tire congurations. Light Truck (LT-Metric) Tire
5-67

After the tires have been rotated, adjust the front
and rear ination pressures as shown on the
Certication/Tire label or Tire and Loading Information
label. SeeInation - Tire Pressure on page 5-70
andLoading Your Vehicle on page 4-29. Make
certain that all wheel nuts are properly tightened.
See “Wheel Nut Torque” underCapacities and
Specications on page 5-107.
{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.
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.
5-72

Buying New Tires
To nd out what kind and size of tires you need, look
at the Certication/Tire label or the Tire and Loading
Information label. SeeLoading Your Vehicle on
page 4-29, for examples of the labels and where they
can be found on your vehicle.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specication (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, speed rating, 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.{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. SeeCompact Spare
Tire on page 5-90.
{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.
5-73

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 or tire chain
clearance to the body and chassis.
SeeChanging a Flat Tire on page 5-78for more
information.
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.
Tire Chains
Notice:Use tire chains only where legal and only
when you must. Use only SAE Class″S″type chains
that are the proper size for your tires. Install them
on the rear axle tires and tighten them as tightly
as possible with the ends securely fastened.
Drive slowly and follow the chain manufacturer’s
instructions. If you can hear the chains contacting
your vehicle, stop and retighten them. If the contact
continues, slow down until it stops. Driving too
fast or spinning the wheels with chains on will
damage your vehicle.
5-76

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. SeeCapacities and
Specifications on page 5-107for the wheel nut
torque specication.
13. Remove the wheel blocks.
Notice:Wheel covers will not t on your compact
spare. If you try to put a wheel cover on the compact
spare, you could damage the cover or the spare.
Storing a Flat or Spare Tire and Tools
{CAUTION:
Storing a jack, a tire, or other equipment in
the passenger compartment of the vehicle
could cause injury. In a sudden stop or
collision, loose equipment could strike
someone. Store all these in the proper place.1. Put the at tire on the ground at the rear of the
vehicle with the valve stem pointed down.
2. Tilt the retainer plate downward and through the
wheel opening. Make sure it is fully seated across
the underside of the wheel. Attach the ratchet,
with the UP side facing you, to the extension.
3. Put the at end of the extension on an angle
through the hole in the rear door frame, above
the bumper.
The compact spare is for temporary use only.
Replace the compact spare tire with a full-size tire
as soon as you can. SeeCompact Spare Tire
on page 5-90. See the storage instructions label
to restore your compact spare properly.
4. Raise the tire fully against the underside of the
vehicle by turning the ratchet/wheel wrench until
you hear two clicks or feel it skip twice. The spare
tire hoist cannot be overtightened.
5-89

5. Make sure the tire is stored securely. Push, pull,
and then try to rotate or turn the tire. If the tire
moves, use the ratchet/wheel wrench to tighten
the cable.
Return the jacking equipment to its proper location.
Compact Spare Tire
Although the compact spare tire was fully inated
when your vehicle was new, it can lose air after a time.
Check the ination pressure regularly. It should be
60 psi (420 kPa).
After installing the compact spare on your vehicle, you
should stop as soon as possible and make sure your
spare tire is correctly inated. The compact spare is
made to perform well at speeds up to 65 mph (105 km/h)
for distances up to 3,000 miles (5 000 km), so you can
nish your trip and have your full-size tire repaired or
replaced where you want. Of course, it’s best to replace
your spare with a full-size tire as soon as you can. Your
spare will last longer and be in good shape in case you
need it again.
Notice:When the compact spare is installed, don’t
take your vehicle through an automatic car wash
with guide rails. The compact spare can get caught
on the rails. That can damage the tire and wheel,
and maybe other parts of your vehicle.
5-90

Storage Areas................................................2-36
Convenience Net.........................................2-43
Luggage Carrier..........................................2-43
Overhead Console.......................................2-38
Storing a Flat or Spare Tire and Tools...............5-89
Stuck in Sand, Mud, Ice or Snow......................4-28
Sun Visors.....................................................2-16
Sunglasses Storage Compartment.....................2-42
T
Taillamps.......................................................5-57
Theft-Deterrent, Radio.....................................3-44
Theft-Deterrent Systems...................................2-17
Passlock
®...................................................2-17
Throttle System Inspection...............................6-27
Tilt Wheel........................................................ 3-5
Tire Ination Check.........................................6-22
Tire Sidewall Labeling......................................5-61
Tire Size.......................................................5-66
Tire Terminology and Denitions........................5-68
Tires.............................................................5-60
Buying New Tires........................................5-73
Chains.......................................................5-76
Changing a Flat Tire....................................5-78
Compact Spare Tire.....................................5-90
If a Tire Goes Flat.......................................5-77Tires (cont.)
Ination - Tire Pressure................................5-70
Inspection and Rotation................................5-71
Uniform Tire Quality Grading.........................5-74
Wheel Alignment and Tire Balance.................5-75
Wheel Replacement.....................................5-75
When It Is Time for New Tires......................5-72
To Use the Engine Coolant Heater....................2-21
Top Strap......................................................1-47
Top Strap Anchor Location...............................1-49
Torque Lock...................................................2-28
Total Weight on Your Vehicle’s Tires..................4-38
Tow/Haul Mode...............................................4-36
Tow/Haul Mode Button.....................................2-24
Tow/Haul Mode Light.......................................3-34
Towing
Recreational Vehicle.....................................4-29
Towing a Trailer..........................................4-35
Your Vehicle...............................................4-29
Trailer Brakes.................................................4-40
Trailer Wiring Harness.....................................4-45
Trailering Package..........................................4-34
Transfer Case................................................5-50
Transmission
Fluid, Automatic...........................................5-23
Transmission Operation, Automatic....................2-22
Transmission, Transaxle, Transfer Case
Unit Repair Manual......................................7-12
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