Vehicle Care 10-51
Vehicle Placard:A label
permanently attached to a
vehicle showing the vehicle's
capacity weight and the
original equipment tire size
and recommended inflation
pressure. See “Tire and Loading
Information Label” underVehicle
Load Limits
on page 9‑27.
Tire Pressure
Tires need the correct amount
of air pressure to operate
effectively.
Notice:Do not let anyone tell
you that under‐inflation or
over‐inflation is all right. It is
not. If your tires do not have
enough air (under‐inflation),
you can get the following:
.Too much flexing
.Too much heat
.Tire overloading
.Premature or
irregular wear
.Poor handling
.Reduced fuel economy
If your tires have too much air
(over‐inflation), you can get
the following:
.Unusual wear
.Poor handling
.Rough ride
.Needless damage from
road hazards
A vehicle specific Tire and
Loading Information label is
attached to your vehicle. This
label shows your vehicle's
original equipment tires and the
correct inflation pressures for
your tires when they are cold.
The recommended cold tire
inflation pressure, shown on the
label, is the minimum amount of air pressure needed to support
your vehicle's maximum load
carrying capacity.
For additional information
regarding how much weight
your vehicle can carry, and an
example of the Tire and Loading
Information label, see
Vehicle
Load Limits
on page 9‑27.
How you load your vehicle
affects vehicle handling and ride
comfort. Never load your vehicle
with more weight than it was
designed to carry.
When to Check
Check your tires once a month
or more. Also check the tire
pressure of the spare tire. If your
vehicle has a compact spare
tire, it should be at 60 psi
(420 kPa). See Full-Size Spare
Tire
on page 10‑85for additional
information.
10-52 Vehicle Care
How to Check
Use a good quality pocket-type
gauge to check tire pressure.
You cannot tell if your tires are
properly inflated simply by
looking at them. Radial tires may
look properly inflated even when
they are underinflated. Check
the tire's inflation pressure when
the tires are cold. Cold means
your vehicle has been sitting for
at least three hours or driven no
more than 1 mile (1.6 km).
Remove the valve cap from the
tire valve stem. Press the tire
gauge firmly onto the valve to
get a pressure measurement.
If the cold tire inflation pressure
matches the recommended
pressure on the Tire and
Loading Information label, no
further adjustment is necessary.
If the inflation pressure is low,
add air until you reach the
recommended amount.If you overfill the tire, release air
by pushing on the metal stem
in the center of the tire valve.
Recheck the tire pressure with
the tire gauge.
Be sure to put the valve caps
back on the valve stems. They
help prevent leaks by keeping
out dirt and moisture.
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 inflated to
the inflation pressure recommended
by the vehicle manufacturer on the vehicle placard or tire inflation
pressure label. (If your vehicle has
tires of a different size than the size
indicated on the vehicle placard or
tire inflation pressure label, you
should determine the proper tire
inflation 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 significantly
under‐inflated.
Accordingly, when the low tire
pressure telltale illuminates, you
should stop and check your tires as
soon as possible, and inflate them
to the proper pressure. Driving on
a significantly under‐inflated tire
causes the tire to overheat and can
lead to tire failure. Under‐inflation
also reduces fuel efficiency and
tire tread life, and may affect the
vehicle's handling and stopping
ability.
10-54 Vehicle Care
If the warning light comes on,
stop as soon as possible and
inflate the tires to the recommended
pressure shown on the tire loading
information label. SeeVehicle Load
Limits on page 9‑27.
At the same time, a Driver
Information Center (DIC) message
is displayed on the DIC display
screen. The low tire pressure
warning light and the DIC warning
message come on at each ignition
cycle until the tires are inflated to
the correct inflation pressure. For
additional information and details
about the DIC operation and
displays see Tire Messages
on
page 5‑25.
The low tire pressure warning light
may come on in cool weather when
the vehicle is first started, and then
turn off as you start to drive. This
could be an early indicator that the
air pressure in the tire(s) are getting
low and need to be inflated to the
proper pressure. A Tire and Loading Information
label, attached to the vehicle, shows
the size of the vehicle's original
equipment tires and the correct
inflation pressure for the vehicle's
tires when they are cold. See
Vehicle Load Limits
on page 9‑27,
for an example of the Tire and
Loading Information label and its
location on the vehicle. Also see
Tire Pressure on page 10‑51.
The vehicle's TPMS can warn you
about a low tire pressure condition
but it does not replace normal tire
maintenance. See Tire Inspection
on page 10‑57,Tire Rotationon
page 10‑57and Tires on
page 10‑44.
Notice: Liquid tire sealants could
damage the Tire Pressure Monitor
System (TPMS) sensors. Sensor
damage caused by using a tire
sealant is not covered by your
warranty. Do not use liquid tire
sealants.
TPMS Malfunction Light and
Message
The TPMS will not function properly
if one or more of the TPMS sensors
are missing or inoperable. When the
system detects a malfunction, the
low tire warning light flashes for
about one minute and then stays on
for the remainder of the ignition
cycle. A DIC warning message is
also displayed. The low tire warning
light and DIC warning message
come on at each ignition cycle until
the problem is corrected. Some of
the conditions that can cause the
malfunction light and DIC message
to come on are:
.One of the road tires has been
replaced with the spare tire.
The spare tire does not have
a TPMS sensor. The TPMS
malfunction light and DIC
message should go off once you
re‐install the road tire containing
the TPMS sensor.
10-58 Vehicle Care
Reset the Tire Pressure Monitor
System. SeeTire Pressure
Monitor Operation
on page 10‑53.
Make certain that all wheel nuts
are properly tightened. See
“Wheel Nut Torque” under
Capacities and Specifications
on
page 12‑2
.
{WARNING
Rust or dirt on a wheel, or on the
parts to which it is fastened, can
make wheel nuts become loose
after time. The wheel could come
off and cause an accident. When
changing a wheel, remove any
rust or dirt from places where the
wheel attaches to the vehicle. In
an emergency, use a cloth or a
paper towel to do this; but be sure
to use a scraper or wire brush
later, if needed, to get all the rust
or dirt off. See If a Tire Goes Flat
on page 10‑64.
When It Is Time for New
Tires
Various factors, such as
maintenance, temperatures, driving
speeds, vehicle loading, and road
conditions influence when you need
new tires.
One way to tell when it is time for
new tires is to check the treadwear
indicators, which appear when the
tires have only 1.6 mm (1/16 inch) or
less of tread remaining. The vehicle needs 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.
Vehicle Care 10-59
The rubber in tires degrades over
time. This is also true for the spare
tire, if the vehicle has one, even
if it is not being used. Multiple
conditions affect how fast this
aging takes place, including
temperatures, loading conditions,
and inflation pressure maintenance.
With proper care and maintenance
tires typically wear out before they
degrade due to age. If you are
unsure about the need to replace
the tires as they get older, consult
the tire manufacturer for more
information.
Buying New Tires
GM has developed and matched
specific tires for your vehicle.
The original equipment tires
installed on your vehicle, when
it was new, were designed tomeet General Motors Tire
Performance Criteria
Specification (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 specifications 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. See
Tire
Sidewall Labeling
on page 10‑44
for additional information.
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.
10-60 Vehicle Care
SeeTire Inspectionon page 10‑57
andTire Rotationon page 10‑57
for information on proper tire
rotation.
{WARNING
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.
{WARNING
If you use bias-ply tires on the
vehicle, the wheel rim flanges
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 the 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.
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. See
Tire Pressure
Monitor System
on page 10‑52.
Your vehicle's original
equipment tires are listed
on the Tire and Loading
Information Label. See Vehicle
Load Limits
on page 9‑27, 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.
Vehicle Care 10-61
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.
{WARNING
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
Hummer specific wheel and tire
systems developed for your
vehicle, and have them properly
installed by a GM certified
technician.
See Buying New Tires
on
page 10‑59and Accessories and
Modificationson page 10‑3for
additional information.
Uniform Tire Quality
Grading
Quality grades can be found
where applicable on the tire
sidewall between tread shoulder
and maximum section width. For
example:
Treadwear 200 Traction AA
Temperature A
The following information relates
to the system developed by the
United States National Highway
Traffic Safety Administration
(NHTSA), which grades tires
by treadwear, traction, and
temperature performance. This
applies only to vehicles sold in
the United States. The grades
are molded on the sidewalls
of most passenger car tires.
The Uniform Tire Quality
Grading (UTQG) system
does not apply to deep
tread, winter-type snow tires, space-saver, or temporary use
spare tires, tires with nominal
rim diameters of 10 to 12 inches
(25 to 30 cm), or to some
limited-production tires.
While the tires available on
Hummer light trucks may vary
with respect to these grades,
they must also conform to
federal safety requirements and
additional General Motors Tire
Performance Criteria (TPC)
standards.
All Passenger Car Tires Must
Conform to Federal Safety
Requirements In Addition To
These Grades.
Treadwear
The treadwear grade is a
comparative rating based
on the wear rate of the tire
when tested under controlled
conditions on a specified
government test course.
10-64 Vehicle Care
Tire Chains
{WARNING
If your vehicle has LT285/75R16
or P265/65R18 size tires, do not
use tire chains. They can damage
your vehicle because 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.(Continued)
WARNING (Continued)
To help avoid damage to your
vehicle, drive slowly, readjust,
or remove the device if it is
contacting your vehicle, and do
not spin your vehicle's wheels.
If you do find traction devices that
will fit, install them on the rear
tires.
Notice: If your vehicle has a tire
size other than LT285/75R16 or
P265/65R18 use tire chains only
where legal and only when you
must. Use chains that are the
proper size for your tires. Install
them on the tires of the rear axle.
Do not use chains on the tires of
the front axle. 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.
If a Tire Goes Flat
It is unusual for a tire to blowout
while you are driving, especially if
you maintain your vehicle's tires
properly. If air goes out of a tire, it is
much more likely to leak out slowly.
But if you should ever have a
blowout, here are a few tips about
what to expect and what to do:
If a front tire fails, the flat tire
creates a drag that pulls the vehicle
toward that side. Take your foot off
the accelerator pedal and grip the
steering wheel firmly. Steer to
maintain lane position, and then
gently brake to a stop well out of the
traffic lane.