tire size GMC ENVOY XL 2006 Owners Manual

Loading Your Vehicle
It is very important to know how much weight your
vehicle can carry. This weight is called the vehicle
capacity weight and includes the weight of all occupants,
cargo, and all nonfactory-installed options. Two labels
on your vehicle show how much weight it was designed
to carry, the Tire and Loading Information label and
the Certication/Tire label.
{CAUTION:
Do not load your vehicle any heavier than the
Gross Vehicle Weight Rating (GVWR), or either
the maximum front or rear Gross Axle Weight
Rating (GAWR). If you do, parts on your
vehicle can break, and it can change the way
your vehicle handles. These could cause you
to lose control and crash. Also, overloading
can shorten the life of your vehicle.
Tire and Loading Information Label
A vehicle specic Tire and Loading Information label is
attached to the center pillar (B-pillar). With the driver’s
door open, you will nd the label attached below
the door lock post (striker). The tire and loading
information label shows the number of occupant seating
positions (A), and the maximum vehicle capacity
weight (B) in kilograms and pounds.
The Tire and Loading Information label also shows the
size of the original equipment tires (C) and the
recommended cold tire ination pressures (D). For more
information on tires and ination seeTires on page 5-55
andInation - Tire Pressure on page 5-62. Label Example
4-45

Certication/Tire Label
A vehicle specic Certication/Tire label is found on the
rear edge of the driver’s door. The label shows the size
of your vehicle’s original tires and the ination pressures
needed to obtain the gross weight capacity of your
vehicle.This is called Gross Vehicle Weight Rating (GVWR). The
GVWR includes the weight of the vehicle, all occupants,
fuel, cargo, and trailer tongue weight, if pulling a trailer.
The Certication/Tire label also tells you the maximum
weights for the front and rear axles, called Gross
Axle Weight Rating (GAWR). To nd out the actual loads
on your front and rear axles, you need to go to a
weigh station and weigh your vehicle. Your dealer can
help you with this. Be sure to spread out your load
equally on both sides of the centerline.
Never exceed the GVWR for your vehicle, or the GAWR
for either the front or rear axle.
And, if you do have a heavy load, you should spread
it out.
Similar appearing vehicles may have different GVWRs
and capacity weights. Please note your vehicle’s
Certication/Tire label or consult your dealer for
additional details.
4-48

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-3
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-5
California Fuel...............................................5-6
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling the Tank..............................................5-8
Filling a Portable Fuel Container.....................5-10
Checking Things Under the Hood....................5-10
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-16
Engine Oil Life System..................................5-20
Engine Air Cleaner/Filter................................5-21
Automatic Transmission Fluid.........................5-23
Engine Coolant.............................................5-25
Radiator Pressure Cap..................................5-28
Engine Overheating.......................................5-28
Cooling System............................................5-30
Engine Fan Noise.........................................5-35Power Steering Fluid.....................................5-36
Windshield Washer Fluid................................5-37
Brakes........................................................5-38
Battery........................................................5-41
Jump Starting...............................................5-42
Rear Axle.......................................................5-47
Four-Wheel Drive............................................5-48
Front Axle......................................................5-49
Bulb Replacement..........................................5-50
Halogen Bulbs..............................................5-50
Headlamps, Front Turn Signal, Sidemarker,
and Parking Lamps....................................5-50
Taillamps, Turn Signal, and Stoplamps............5-51
Back-Up Lamps............................................5-52
Replacement Bulbs.......................................5-52
Windshield Wiper Blade Replacement..............5-53
Tires..............................................................5-55
Tire Sidewall Labeling...................................5-56
Tire Terminology and Denitions.....................5-59
Ination - Tire Pressure.................................5-62
Tire Inspection and Rotation...........................5-63
When It Is Time for New Tires.......................5-65
Buying New Tires.........................................5-66
Different Size Tires and Wheels......................5-67
Uniform Tire Quality Grading..........................5-68
Section 5 Service and Appearance Care
5-1

Tire Sidewall Labeling
Useful information about a tire is molded into the
sidewall. The following illustrations are examples of a
typical P-Metric and a LT-Metric tire sidewall.
(A) Tire Size:The tire size code is a combination of
letters and numbers used to dene 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) TPC Spec (Tire Performance Criteria
Specication):Original equipment tires designed to
GM’s specic tire performance criteria have a TPC
specication code molded onto the sidewall. GM’s TPC
specications meet or exceed all federal safety
guidelines.
(C) DOT (Department of Transportation):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 Identication
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 5-68.
(G) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For information on
recommended tire pressure seeInation - Tire Pressure
on page 5-62andLoading Your Vehicle on page 4-45. Passenger (P-Metric) Tire
5-56

(A) Tire Size:The tire size code is a combination of
letters and numbers used to dene 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) TPC Spec (Tire Performance Criteria
Specication):Original equipment tires designed to
GM’s specic tire performance criteria have a TPC
specication code molded onto the sidewall.GM’s TPC specications 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 conguration. For
information on recommended tire pressure see
Ination - Tire Pressure on page 5-62andLoading Your
Vehicle on page 4-45.
(D) DOT (Department of Transportation):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 Identication Number (TIN):The letters and
numbers following DOT code are the Tire Identication
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
Ination - Tire Pressure on page 5-62andLoading
Your Vehicle on page 4-45. Light Truck (LT-Metric) Tire
5-57

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.(A) Light Truck (LT-Metric) Tire:The United States
version of a metric tire sizing system. The letters 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
light truck (LT-Metric) tire 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. Passenger (P-Metric) Tire
Light Truck (LT-Metric) Tire
5-58

Sidewall:The portion of a tire between the tread and
the bead.
Speed Rating:An alphanumeric code assigned to a
tire indicating the maximum speed at which a tire
can operate.
Traction:The friction between the tire and the road
surface. The amount of grip provided.
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 1/16 inch (1.6 mm) of tread remains.
SeeWhen It Is Time for New Tires on page 5-65.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 5-68.
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 4-45.
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 vehicle’s capacity weight and
the original equipment tire size and recommended
ination pressure. See “Tire and Loading Information
Label” underLoading Your Vehicle on page 4-45.
5-61

When It Is Time for New Tires
One way to tell when it is
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
cannot be repaired well because of the size or
location of the damage.
5-65

Buying New Tires
GM has developed and matched specic tires for your
vehicle. The original equipment tires installed on
your vehicle, when it was new, were designed to meet
General Motors Tire Performance Criteria Specication
(TPC spec) system rating. If you need replacement
tires, GM strongly recommends that you get tires with
the same TPC Spec rating. This way, your vehicle
will continue to have tires that are designed to give the
same performance and vehicle safety, during normal
use, as the original tires.
GM’s exclusive TPC Spec system considers over a
dozen critical specications that impact the overall
performance of your vehicle, including brake system
performance, ride and handling, traction control, and tire
pressure monitoring performance.GM’s TPC Spec number is molded onto the tire’s
sidewall by the tire manufacturer. If the tires have an
all-season tread design, the TPC spec number will
be followed by a MS, for mud and snow. SeeTire
Sidewall Labeling on page 5-56for additional
information.
{CAUTION:
Mixing tires could cause you to lose control
while driving. If you mix tires of different sizes,
brands, or types (radial and bias-belted tires)
the vehicle may not handle properly, and you
could have a crash. Using tires of different
sizes, brands, or types may also cause
damage to your vehicle. Be sure to use the
correct size, brand, and type of tires on your
vehicle’s wheels.
5-66

{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.
If you must replace your vehicle’s tires with those that
do not have a TPC Spec number, make sure they
are the same size, load range, speed rating, and
construction type (radial and bias-belted tires) as your
vehicle’s original tires.
Your vehicle’s original equipment tires are listed on the
Tire and Loading Information Label. This label is
attached to the vehicle’s center pillar (B-pillar). See
Loading Your Vehicle on page 4-45, for more information
about the Tire and Loading Information Label.
Different Size Tires and Wheels
If you add wheels or tires that are a different size than
your original equipment wheels and tires, this may
affect the way your vehicle performs, including its
braking, ride and handling characteristics, stability, and
resistance to rollover. Additionally, if your vehicle
has electronic systems such as, anti-lock brakes,
traction control, and electronic stability control, the
performance of these systems can be affected.
{CAUTION:
If you add different sized wheels, your vehicle
may not provide an acceptable level of
performance and safety if tires not
recommended for those wheels are selected.
You may increase the chance that you will
crash and suffer serious injury. Only use GM
specic wheel and tire systems developed for
your vehicle, and have them properly installed
by a GM certied technician.
SeeBuying New Tires on page 5-66andAccessories
and Modications on page 5-3for additional information.
5-67