wheel size GMC ENVOY XL 2004 Owners Manual

(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”.(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.Light Truck (LT-Metric) Tire
5-60

(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.
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)
or kilopascals (kPa) before a tire has built up heat from
driving. SeeInation - Tire Pressure on page 5-64.
Curb Weight:This means the weight of a motor vehicle
with standard and optional equipment including the
maximum capacity of fuel, oil and coolant, but without
passengers and cargo.
DOT Markings:A code molded into the sidewall
of a tire signifying that the tire is in compliance with
the U.S. Department of Transportation motor vehicle
safety standards. The DOT code includes the Tire
Identication Number (TIN), an alphanumeric designator
which can also identify the tire manufacturer, production
plant, brand and date of production.
5-61

After the tires have been rotated, adjust the front and rear
ination pressures as shown on the Certication/Tire
label or the Tire and Loading Information label. Make
certain that all wheel nuts are properly tightened. See
“Wheel Nut Torque” underCapacities and Specications
on page 5-109.
{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.
5-66

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. For examples of these labels and their
location on your vehicle, seeLoading Your Vehicle
on page 4-49.
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,
General Motors 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, 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.{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.
{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.
5-67

Tire Chains
{CAUTION:
Don’t use tire chains. There’s not enough
clearance. Tire chains used on a vehicle without
the proper amount of clearance can cause
damage to the brakes, suspension or other
vehicle parts. The area damaged by the tire
chains could cause you to lose control of your
vehicle and you or others may be injured in a
crash. Use another type of traction device only
if its manufacturer recommends it for use on
your vehicle and tire size combination and road
conditions. Follow that manufacturer’s
instructions. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it’s contacting your vehicle, and don’t
spin your wheels. If you do nd traction devices
that will t, install them on the rear tires.
Accessory Inator
Your vehicle may be equipped with an air inator
system. You can inate things like basketballs and
bicycle tires. Also, you can use it to bring your tire
pressure up to the proper pressure. It is not designed
to inate large objects which will require more than ve
minutes to inate, such as an air mattress.
The air inator is
located in the rear
compartment on the
passenger’s side of
the vehicle behind
an access cover.
To remove the cover, pull the two tabs on the cover
and pull it off.
The air inator kit includes a 22 ft (6.7 m) hose with
three nozzle adapters.
5-71

T
Tachometer....................................................3-37
Taillamps
Turn Signal Lamps......................................5-52
Testing the Alarm............................................2-18
Theft-Deterrent, Radio....................................3-119
Theft-Deterrent Systems...................................2-17
Content Theft-Deterrent................................2-17
Passlock
®...................................................2-19
Throttle, Adjustable..........................................2-22
TIGHTEN FUEL CAP......................................3-63
Tilt Wheel........................................................ 3-7
Tire Sidewall Labeling......................................5-56
Tire Size.......................................................5-59
Tire Terminology and Denitions........................5-61
Tires.............................................................5-55
Buying New Tires........................................5-67
Chains.......................................................5-71
Changing a Flat Tire....................................5-74
If a Tire Goes Flat.......................................5-73
Ination - Tire Pressure................................5-64
Inspection and Rotation................................5-65
Spare Tire..................................................5-87
Uniform Tire Quality Grading.........................5-68
Wheel Alignment and Tire Balance.................5-69
Wheel Replacement.....................................5-69
When It Is Time for New Tires......................5-66
To Use the Engine Coolant Heater....................2-23Top Strap......................................................1-37
Top Strap Anchor Location...............................1-39
Torque Lock...................................................2-32
Total Weight on Your Vehicle’s Tires..................4-59
Towing
Recreational Vehicle.....................................4-45
Towing a Trailer..........................................4-55
Your Vehicle...............................................4-45
Traction
Assist System (TAS)...................................... 4-9
Trailer Brakes.................................................4-60
Trailer Wiring Harness.....................................4-66
Transfer Case................................................5-49
Transmission
Fluid, Automatic...........................................5-22
Transmission Operation, Automatic....................2-24
Transmission, Transaxle, Transfer Case
Unit Repair Manual......................................7-12
Transportation Options...................................... 7-9
Travel Note Recorder......................................2-47
Traveling to Remote Areas...............................4-18
Trip Information..............................................3-51
Trip Odometer................................................3-37
Turn and Lane Change Signals.......................... 3-8
TURN SIGNAL ON.........................................3-61
Turn Signal/Multifunction Lever........................... 3-7
Turn Signals When Towing a Trailer..................4-63
Two-Wheel-Drive Vehicles................................4-46
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