2008 GMC ENVOY tire size

If your vehicle has P255/50R20 104V size tires installed
on the rear axle, they will require ination pressure
adjustment when driving your vehicle at speeds above
99 mph (160 km/h). Set the cold ination pressure, for
the rear tires only, to the maximum ination pressure
shown on the tire sidewall, or 38 psi (262 kPa), whichever
is lower. See the example following. When you end this
high-speed driving, return the tires to the cold tire ination
pressure shown on the Tire and Loading Information
label. SeeLoading Your Vehicle on page 4-34.
Example:
You will nd the maximum load and ination pressure
molded on the tire’s sidewall, in small letters, near
the rim ange. It will read something like this: Maximum
load 690 kg (1521 lbs) 300 kPa (44 psi) Max. Press.
For this example, you would set the ination pressure for
high-speed driving at 38 psi (262 kPa).
The ination pressure for the front tires should be set to
the cold tire ination pressure shown on the Tire and
Loading Information label.
Racing or other competitive driving may affect the
warranty coverage of your vehicle. See your warranty
booklet for more information.Tire Pressure Monitor System
The Tire Pressure Monitor System (TPMS) uses radio
and sensor technology to check tire pressure levels. The
TPMS sensors monitor the air pressure in your vehicle’s
tires and transmit tire pressure readings to a receiver
located in the vehicle.
Each tire, including the spare (if provided), should be
checked monthly when cold and inated to the ination
pressure recommended by the vehicle manufacturer
on the vehicle placard or tire ination pressure label.
(If your vehicle has tires of a different size than the
size indicated on the vehicle placard or tire ination
pressure label, you should determine the proper
tire ination pressure for those tires.)
As an added safety feature, your vehicle has been
equipped with a tire pressure monitoring system (TPMS)
that illuminates a low tire pressure telltale when one or
more of your tires is signicantly under-inated.
Accordingly, when the low tire pressure telltale
illuminates, you should stop and check your tires as
soon as possible, and inate them to the proper
pressure. Driving on a signicantly under-inated tire
causes the tire to overheat and can lead to tire failure.
Under-ination also reduces fuel efficiency and tire
tread life, and may affect the vehicle’s handling and
stopping ability.
5-67

Tire Pressure Monitor Operation
The Tire Pressure Monitor System (TPMS) is designed
to warn the driver when a low tire pressure condition
exists. TPMS sensors are mounted onto each tire
and wheel assembly, excluding the spare tire and wheel
assembly. The TPMS sensors monitor the air pressure
in the vehicle’s tires and transmit the tire pressure
readings to a receiver located in the vehicle.
The TPMS is designed to alert the driver if a low tire
pressure condition exists. If your vehicle has the Driver
Information Center (DIC) steering wheel control
buttons, tire pressure levels may also be checked
through the DIC. See “Tire Pressures” underDIC
Operation and Displays on page 3-50.
When a low tire pressure
condition is detected, the
TPMS illuminates the
low tire pressure warning
light located on the
instrument panel cluster.At the same time a message to check the pressure in a
specic tire appears on the Driver Information Center
(DIC) display. The low tire pressure warning light
and the DIC warning message come on at each ignition
cycle until the tires are inated to the correct ination
pressure. Using the DIC, tire pressure levels can be
viewed by the driver. For additional information and
details about the DIC operation and displays seeDIC
Operation and Displays on page 3-50andDIC Warnings
and Messages on page 3-53.
The low tire pressure warning light may come on in cool
weather when the vehicle is rst started, and then
turn off as you start to drive. This could be an early
indicator that the air pressure in the tire(s) is low
and needs to be inated to the proper pressure.
A Tire and Loading Information label, attached to your
vehicle, shows the size of your vehicle’s original
equipment tires and the correct ination pressure for
your vehicle’s tires when they are cold. SeeLoading
Your Vehicle on page 4-34, for an example of the Tire
and Loading Information label and its location on
your vehicle. Also seeInflation - Tire Pressure on
page 5-64.
5-69

You need new tires 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.
The rubber in tires degrades over time, even if they are
not being used. This is also true for the spare tire, if
your vehicle has one. Multiple conditions affect how fast
this aging takes place, including temperatures, loading
conditions, and ination pressure maintenance. With
proper care and maintenance tires will typically wear out
before they degrade due to age. If you are unsure about
the need to replace your tires as they get older, consult
the tire manufacturer for more information.
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 near the tire size. 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 5-58for
additional information.
5-74

GM recommends replacing tires in sets of four.
This is because uniform tread depth on all tires will
help keep your vehicle performing most like it did
when the tires were new. Replacing less than a full
set of tires can affect the braking and handling
performance of your vehicle. SeeTire Inspection
and Rotation on page 5-72for information on
proper tire rotation.
{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.
{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.
5-75

Vehicles equipped with a tire pressure monitoring
system may give an inaccurate low-pressure
warning if non-TPC spec rated tires are installed
on your vehicle. Non-TPC Spec rated tires may
give a low-pressure warning that is higher or lower
than the proper warning level you would get with
TPC Spec rated tires. SeeTire Pressure Monitor
System on page 5-67.
Your vehicle’s original equipment tires are listed
on the Tire and Loading Information Label. See
Loading Your Vehicle on page 4-34, for more
information about the Tire and Loading Information
Label and its location on your vehicle.
Different Size Tires and Wheels
If you add wheels or tires that are a different size than
your original equipment wheels and tires, this could
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, rollover
airbags, 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 5-74andAccessories
and Modifications on page 5-3for additional information.
5-76

Tire Chains
{CAUTION:
Do not use tire chains. There is 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, re-adjust or remove the
device if it is contacting your vehicle, and do
not spin your wheels. If you do nd traction
devices that will t, install them on the
rear tires.
Accessory Inator
Your vehicle may have an accessory inator system.
You can inate things like basketballs and bicycle tires.
You can also 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 accessory inator is
located in the rear
compartment on the
driver’s side of the vehicle
behind an access cover,
near the liftgate opening.
To remove the cover, push in on the tab to access the
inator.
You may have an air inator kit that is located in the
glove compartment. It includes a 22 ft (6.7 m) hose with
three nozzle adapters.
5-80

1. Attach the handle (A), wheel wrench (B), and
extension (D) in the slots provided.
2. Roll up the instruction label (C) and return to the
slot in the tool kit.
3. Assemble the wheel blocks (F) to the jack.
4. Turn the knob (E) on the jack clockwise to raise the
jack head.
5. Return the rear seat to its proper position.
Spare Tire
Your vehicle, when new, had a fully-inated spare tire.
A spare tire may lose air over time, so check its
ination pressure regularly. SeeInflation - Tire Pressure
on page 5-64andLoading Your Vehicle on page 4-34
for information regarding proper tire ination and loading
your vehicle. For instruction on how to remove, install
or store a spare tire, seeRemoving the Flat Tire and
Installing the Spare Tire on page 5-87andStoring a Flat
or Spare Tire and Tools on page 5-96.After installing the spare tire on your vehicle, you should
stop as soon as possible and make sure the spare is
correctly inated. The spare tire is made to perform well
at speeds up to 70 mph (112 km/h) at the recommended
ination pressure, so you can nish your trip.
Have the damaged or at road tire repaired or replaced
as soon as you can and installed back onto your
vehicle. This way, a spare tire will be available in case
you need it again. Do not mix tires and wheels of different
sizes, because they will not t. Keep your spare tire and
its wheel together.
5-99

Tires.............................................................5-57
Aluminum Wheels, Cleaning........................5-105
Buying New Tires........................................5-74
Chains.......................................................5-80
Changing a Flat Tire....................................5-82
Cleaning...................................................5-106
Different Size..............................................5-76
High-Speed Operation..................................5-66
If a Tire Goes Flat.......................................5-81
Ination - Tire Pressure................................5-64
Inator,- Accessory.......................................5-80
Inspection and Rotation................................5-72
Installing the Spare Tire................................5-87
Pressure Monitor Operation...........................5-69
Pressure Monitor System..............................5-67
Removing the Flat Tire.................................5-87
Removing the Spare Tire and Tools...............5-84
Secondary Latch System..............................5-92
Spare Tire..................................................5-99
Storing a Flat or Spare Tire and Tools............5-96
Tire Sidewall Labeling..................................5-58
Tire Terminology and Denitions....................5-61
Uniform Tire Quality Grading.........................5-77
Wheel Alignment and Tire Balance.................5-78
Wheel Replacement.....................................5-78
When It Is Time for New Tires......................5-73Towing
Recreational Vehicle.....................................4-40
Towing a Trailer..........................................4-45
Your Vehicle...............................................4-40
Traction
StabiliTrak
®System....................................... 4-6
Transmission
Fluid, Automatic...........................................5-23
Transmission Operation, Automatic....................2-26
Trip Odometer................................................3-32
Turn and Lane-Change Signals.......................... 3-7
Turn Signal/Multifunction Lever........................... 3-7
U
Uniform Tire Quality Grading............................5-77
Universal Home Remote System.......................2-52
Operation...................................................2-52
Using this Manual............................................... iii
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