GMC SIERRA 1998 Owners Manual

Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer.
If you ever have questions
about your tire warranty and where to obtain service, see
your
GM Warranty booklet for details.
A CAUTION:
Poorly maintained and improperly used tires
are dangerous.
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0
0
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Overloading your tires can cause
overheating as
a result of too much friction.
You could have an air-out and
a serious
accident. See “Loading Your Vehicle” in
the Index. Underinflated tires pose the same danger as
overloaded tires. The resulting accident could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked when your tires are cold.
Overinflated tires are more likely to be cut,
punctured
or broken by a sudden impact --
such as when you hit a pothole. Keep tires
at the recommended pressure.
Worn, old tires can cause accidents. If your
tread is badly worn, or if your tires have
been damaged, replace them.
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Inflation -- Tire Pressure
The CertificationlTire label, which is on the rear edge of
the driver’s door, or on the incomplete vehicle document
in the cab, shows the correct inflation pressures for your
tires when they’re cold.
“Cold” means your vehicle has
been sitting for at least three hours or driven no more
than
1 mile (1.6 krn).
NOTICE:
Don’t let anyone tell you that underinflation or
overinflation is all right.
It’s not. If your tires
don’t have enough
air (underinflation), you can
get the following:
0 Too much flexing
Too much heat
0 Tire overloading
0 Bad wear
Bad handling
0 Bad fuel economy.
If your tires have too much air (overinflation),
you can get the following:
0 Unusual wear
0 Bad handling
0 Rough ride
0 Needless damage from road hazards.
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When to Check
Check your tires once a month or more. Also, check the
tire pressure of the spare tire.
How to Check
Use a good quality pocket-type gage to check tire
pressure. You can’t tell if your tires are properly inflated
simply by looking at them. Radial tires may
look
properly inflated even when they’re underinflated.
Be sure
to put the valve caps back on the valve stems.
They help prevent leaks by keeping out dirt and moisture.
Tire Inspection and Rotation
Tires should be rotated every 6,000 to 8,000 miles
(10 000 to 13 000 km). Any time you notice unusual
wear, rotate your tires as soon as possible and check
wheel alignment.
Also check for damaged tires or
wheels.
See “When It‘s Time for New Tires” and
“Wheel Replacement” later in this section for more
information. If your vehicle has dual rear wheels, also
see “Dual Tire Operation” later
in this section. The purpose
of regular rotation
is to achieve more
uniform wear
for all tires on the vehicle. The first
rotation is the most important. See “Scheduled
Maintenance Services”
in the Index for scheduled
rotation intervals.
1
FRT FRT
[x[
If your vehicle has single rear wheels, always use one of
the correct rotation patterns shown here when rotating
your tires.
If your vehicle has front tires with different load ranges
or tread designs (such as all season vs. on/off road) than
the rear tires, don’t rotate your tires front
to rear.
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~ 11 your
vehicle has dual rear wheels and the load range
’ and tread design for your front tires is the same as your
rear tires, always use one of the correct rotation patterns
shown here when rotating your tires.
r.
If your vehicle has dual rear wheels and the load range
or tread design for your front tires is different from your
rear tires, always use the correct rotation pattern shown
here when rotating your tires. The dual tires are rotated
as a pair, and the inside rear tires become the outside
rear tires.
When you install dual wheels, be sure the vent holes in
the inner and outer wheels on each side are lined up.
After the tires have been rotated, adjust the front and
rear inflation pressures as shown
on the
Certificatioflire label. Make certain that all wheel nuts
are properly tightened. See “Wheel Nut Torque’’ in
the Index.
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A 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.)
1 When It’s 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.
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You need a new tire if any of the following statements
are true:
0 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.
Dual Tire Operation
When the vehicle is new, or whenever a wheel, wheel
bolt or wheel
nut is replaced, check the wheel nut
torque after 100, 1,000 and 6’000 miles (160, 1 600 and
10 000 km) of driving. For proper torque, see “Wheel
Nut Torque”
in the Index. The outer
tire
on a dual wheel setup generally wears
Faster than the inner tire. Your tires will wear more
evenly and last longer if
you rotate the tires periodically.
If you’re going to be doing a lot
of driving on
high-crown roads,
you can reduce tire wear by adding
5 psi (35 kPa) to the tire pressure in the outer tires. Be
sure to return to the recommended pressures when
no
longer driving under those conditions. See “Changing a
Flat Tire’’ in the Index for more information.
If you operate your vehicle with a tire that is badly
underinflated, the tire can overheat. An overheated
tire can lose air suddenly or catch fire.
You or
others could be injured. Be sure all tires (including
the spare,
if any) are properly inflated.
Buying New Tires
To find out what kind and size of tires you need, look at
the CertificatiodTire label.
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The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specification (TPC Spec)
number on each tire’s sidewall. When
you get new tires,
get ones 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,
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.
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.
I A CAUTION:
If you use biasuply tires on your 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 your vehicle.
Uniform Tire Quality Grading
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
I 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 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 I2 inches (25 to 30 cm),
or to some limited-production tires.
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While the tires available on General Motors passenger
cars and 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.
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. For
example, a tire graded 150 would wear one and a half
(1 1/2) 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 -- A, B, C
The traction grades, from highest to lowest, are A, B, and
C, and they 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 braking (straight ahead) traction tests and does not
include cornering (turning) traction.
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 Vehicle 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.
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Wheel Alignment and Tire Balance
The wheels on your vehicle were aligned and balanced
carefully at the factory to give you the longest tire life
and best overall performance.
Scheduled wheel alignment and wheel balancing are not
needed. However,
if you notice unusual tire wear or
your vehicle pulling one way or the other, the alignment
may need to be reset.
If you notice your vehicle
vibrating when driving on a smooth road, your wheels
may need to be rebalanced.
Wheel Replacement
Replace any wheel that is bent, cracked, or badly rusted
or corroded. If wheel nuts keep corning 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 your wheels, wheel bolts
or wheel nuts, replace them only with new
GM original equipment
parts. This way, you will be sure to have the
right wheel, wheel bolts and wheel nuts for your vehicle.
~ 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.
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Whenever a wheel, wheel bolt or wheel nut is replaced
on
a dual wheel setup, check the wheel nut torque after
100, 1,000 and 6,000 miles ( 160, 1 600 and 10 000 km)
of driving. For proper torque, see “Wheel Nut Torque’’
in the Index.
See “Changing
a Flat Tire” in the Index for
more information.
Used Replacement Wheels
/!1 CAUTION:
Putting a used wheel on your vehicle is
dangerous.
You can’t know how it’s been used or
how
far it’s been driven. It could fail suddenly
and cause an accident. If
you have to replace a
wheel, use a new GM original equipment wheel.
Tire Chains
NOTICE:
If your vehicle has dual wheels, P265/75R16 or
LT265/75R16 size tires, don’t use tire chains.
They can damage your vehicle because there’s
not enough clearance.
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 find traction devices that will fit, install
them on the rear tires.
NOTICE: (Continued)
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