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.
10-62 Vehicle Care
For example, a tire graded 150
would wear one and a half (1½)
times as well on the government
course as a tire graded 100.
The relative performance of
tires depends upon the actual
conditions of their use, however,
and may depart significantly
from the norm due to variations
in driving habits, service
practices and differences in
road characteristics and climate.
Traction–AA, A, B, C
The traction grades, from
highest to lowest, are AA, A, B,
and C. Those grades represent
the tire's ability to stop on wet
pavement as measured under
controlled conditions on
specified government test
surfaces of asphalt and
concrete. A tire marked C may
have poor traction performance. Warning: The traction grade
assigned to this tire is based
on straight-ahead braking
traction tests, and does not
include acceleration, cornering,
hydroplaning, or peak traction
characteristics.
Temperature
–A, B, C
The temperature grades are
A (the highest), B, and C,
representing the tire's resistance
to the generation of heat and
its ability to dissipate heat
when tested under controlled
conditions on a specified indoor
laboratory test wheel. Sustained
high temperature can cause
the material of the tire to
degenerate and reduce tire life,
and excessive temperature
can lead to sudden tire failure.
The grade C corresponds to a
level of performance which all
passenger car tires must meet
under the Federal Motor Safety Standard No. 109. Grades B
and A represent higher levels of
performance on the laboratory
test wheel than the minimum
required by law. Warning: The
temperature grade for this tire is
established for a tire that is
properly inflated and not
overloaded. Excessive speed,
underinflation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.
Wheel Alignment and Tire
Balance
The tires and wheels on the vehicle
were aligned and balanced carefully
at the factory to give the longest tire
life and best overall performance.
Adjustments to wheel alignment and
tire balancing will not be necessary
on a regular basis. However, if there
is unusual tire wear or the vehicle
pulls to one side or the other, the
alignment should be checked.
Vehicle Care 10-63
If the vehicle vibrates when
driving on a smooth road, the tires
and wheels might need to be
rebalanced. See your dealer for
proper diagnosis.
Wheel Replacement
Replace any wheel that is bent,
cracked, or badly rusted or
corroded. If wheel nuts keep coming
loose, the wheel, wheel bolts, and
wheel nuts should be replaced.
If the wheel leaks air, replace it
(except some aluminum wheels,
which can sometimes be repaired).
See your dealer if any of these
conditions exist.
Your dealer will know the kind of
wheel you need.
Each new wheel should have the
same load-carrying capacity,
diameter, width, offset, and be
mounted the same way as the
one it replaces.If you need to replace any of the
wheels, wheel bolts, wheel nuts,
or Tire Pressure Monitor System
(TPMS) sensors, replace them only
with new GM original equipment
parts. This way, you will be sure to
have the right wheel, wheel bolts,
wheel nuts, and TPMS sensors for
the vehicle.
{WARNING
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.
See If a Tire Goes Flat
on
page 10‑64for more information.
Used Replacement Wheels
{WARNING
Putting a used wheel on the
vehicle is dangerous. You cannot
know how it has been used or
how far it has been driven.
It could fail suddenly and cause a
crash. If you have to replace a
wheel, use a new GM original
equipment wheel.
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.
10-86 Vehicle Care
After installing the spare tire on your
vehicle, you should stop as soon as
possible and make sure the spare is
correctly inflated.
The spare tire does not have a Tire
Pressure Monitor System sensor.
You may get a low pressure warning
light. SeeTire Pressure Monitor
Operation
on page 10‑53. Have the
damaged or flat road tire repaired or
replaced as soon as you can.
Do not mix tires and wheels of
different sizes, because they will
not fit. Keep your spare tire and its
wheel together.
Jump Starting
If the vehicle's battery has run
down, you may want to use another
vehicle and some jumper cables to
start your vehicle. Be sure to use
the following steps to do it safely.
{WARNING
Batteries can hurt you. They can
be dangerous because:
.They contain acid that can
burn you.
.They contain gas that can
explode or ignite.
.They contain enough
electricity to burn you.
If you do not follow these steps
exactly, some or all of these
things can hurt you. Notice:
Ignoring these steps
could result in costly damage to
the vehicle that would not be
covered by the warranty.
Trying to start the vehicle by
pushing or pulling it will not
work, and it could damage the
vehicle.
1. Check the other vehicle. It must
have a 12‐volt battery with a
negative ground system.
Notice: If the other vehicle's
system is not a 12-volt system
with a negative ground, both
vehicles can be damaged. Only
use vehicles with 12-volt systems
with negative grounds to jump
start your vehicle.
2. Get the vehicles close enough so the jumper cables can reach,
but be sure the vehicles are not
touching each other. If they
are, it could cause a ground
connection you do not want.