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
Tire overloading
Bad wear
0 Bad handling
Bad fuel economy
If your tires have too much air (overinflation), you
can get the following:
Unusual wear
Bad handling
0 Rough ride
Needless damage from road hazards
When to Check
Check your tires once a month or more.
Don’t forget your compact spare tire. It should be at
60 psi (420 kPa).
woav 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.
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Check Tire Pressure System
The check tire pressure system can alert you to a large
change in the pressure of one tire. The system won’t
alert you before you drive that a tire is low or flat.
You must begin driving before the system will work
properly.
The
LOW TIRE PRESSURE message will appear on
the Driver Information Center (DIC)
if pressure difference
(low pressure) is detected in one tire. The check tire
pressure system may not alert you
if:
more than one tire is low,
the vehicle is moving faster than 65 mph (105 km/h),
the system is not yet calibrated,
the tire treadwear is uneven,
the compact spare tire is installed,
tire chains are being used, or
the vehicle is being driven on a rough or
frozen road.
If the anti-lock brake system warning light comes on,
the check tire pressure system may not be working
properly. See your dealer for service.
Also, see
Anti-Lock Brake System Warning Light on page 3-36.
The check tire pressure system detects differences
in tire rotation speeds that are caused by changes in tire
pressure. The system can alert you about a low
tire
- but it doesn’t replace normal tire maintenance.
See
Tires on page 5-60.
When the LOW TIRE PRESSURE message appears on
the Driver Information Center, you should stop as
soon as you can and check all your tires for damage. If
a tire is flat, see
If a Tire Goes Flat on page 5-70.
Also check the tire pressure in all four tires as soon as
you can. See
Inflation -- Tire Pressure on page 5-60.
Any time you adjust a tire’s pressure or have one
or more tires repaired or replaced, you’ll need to reset
(calibrate) the check tire pressure system. You’ll
also need to reset the system whenever you rotate the
tires, buy new tires and install or remove the compact
spare.
Don’t reset the check tire pressure system without first
correcting the cause of the problem and checking
and adjusting the pressure in all four tires.
If you reset
the system when the tire pressures are incorrect,
the check tire pressure system will not work properly
and may not alert you when a tire is low or high.
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To reset (calibrate) the system:
1. Turn the ignition switch to ON.
2. Press the SELECT right arrow on the DIC until you
enter the GAGE mode. Then press the SELECT
down arrow until TIRE PRESSURE appears on the
display.
3. Press and hold the DIC RESET button for about
five seconds. After five seconds, the display will
show TIRE PRESSURE RESET. If TIRE
PRESSURE RESET does not appear on the
display after about five seconds, see your dealer for
service. After you release the DIC RESET button,
TIRE PRESSURE NORMAL will appear on the
display.
The system completes the calibration process during
driving. Calibration time can take
45 to 90 minutes,
depending on your driving habits. After the system has
been calibrated, the system will alert the driver that
a tire is low, up to a maximum speed of
65 mph
(1 05 km/h).
Tire Inspection and Rotation
Tires should be rotated every 7,500 miles (1 2 500 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 Is Time
for New Tires on page 5-65 and Wheel Replacement
on page
5-68 for more information.
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 “Part A: Scheduled
Maintenance Services,” in Section
6, for scheduled
rotation intervals.
When rotating your tires, always use the correct rotation
pattern shown here.
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Don’t include the compact spare tire in your tire rotation.
After the tires have been rotated, adjust the front and
rear inflation pressures as shown on the Tire-Loading
Information label.
Reset the Check Tire Pressure System. See
Check Tire
Pressure System on page
5-62.
Make certain that all wheel nuts are properly tightened.
See Wheel Nut Torque in
Capacities and Specifications
on page
5- 100.
I 1 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 Flal
Tire” in the Index.
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When It Is 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. You need a new
tire
if any of the following statements
are true:
You can see the indicators at three or more places
You can see cord or fabric showing through the
around
the tire.
tire’s rubber.
0 The tread or sidewall is cracked, cut or snagged
0 The tire has a bump, bulge or split.
The tire has a puncture, cut or other damage that
deep enough
to show
cord or fabric.
can’t be repaired well because of the size or
location of the damage.
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Buying New Tires
To find out what kind and size of tires you need, look at
the Tire-Loading Information label.
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.
IL....; tires could cause yo^ .o 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.
It's all right to drive with your
compact spare, though.
It was developed for
use on your vehicle.
If you use bias-ply tires
a lr 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.
I
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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, 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
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 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
(1.5) 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, hydroplaninGr or peak traction characteristics.
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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.
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 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.
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