tires GMC SONOMA 2001 Owner's Guide

6-49
If your vehicle has a compact spare tire, don't include it
in your tire rotation.
After the tires have been rotated, adjust the front and
rear inflation pressures as shown on the
Certification/Tire label. Make certain that all wheel nuts
are properly tightened. See ªWheel Nut Torqueº in
the Index.
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 ªChanging a Flat Tireº in the Index.
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.
You need a new tire 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
can't be repaired well because of the size or location
of the damage.

6-50 Buying New Tires
To find out what kind and size of tires you need,
look at the Certification/Tire 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 ªMSº (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.
CAUTION:
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.
It's all right to drive with your compact spare
(if you have one). It was developed for use on
your vehicle.
CAUTION:
If you use bias-ply 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.

6-51 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 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
-- 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.

6-52
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.

6-53
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.
CAUTION:
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 ªChanging a Flat Tireº in the Index for
more information.
Used Replacement Wheels
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.

6-54 Tire Chains
NOTICE:
If your vehicle has P235/75R15, P235/70R15,
P235/55R16 or 31x10.50R15LT/C 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.
NOTICE: (Continued)
NOTICE: (Continued)
If you do find traction devices that will fit,
install them on the rear tires.
If you have other size tires, use tire chains only
where legal and only when you must. Use only
SAE Class ªSº type chains that are the proper
size for your tires. Install them on the drive axle
tires (four
-wheel-drive vehicles can use chains on
both axles) and 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.

6-60
Cleaning Aluminum Wheels
(If Equipped)
Keep your wheels clean using a soft clean cloth
with mild soap and water. Rinse with clean water.
After rinsing thoroughly, dry with a soft clean towel.
A wax may then be applied.
The surface of these wheels is similar to the painted
surface of your vehicle. Don't use strong soaps,
chemicals, abrasive polishes, abrasive cleaners, cleaners
with acid or abrasive cleaning brushes on them because
you could damage the surface. Do not use chrome polish
on aluminum wheels.
Don't take your vehicle through an automatic car wash
that has silicon carbide tire cleaning brushes. These
brushes can also damage the surface of these wheels.
Cleaning Tires
To clean your tires, use a stiff brush with a tire cleaner.
NOTICE:
When applying a tire dressing always take care to
wipe off any overspray or splash from all painted
surfaces on the body or wheels of the vehicle.
Petroleum
-based products may damage the paint
finish and tires.
Sheet Metal Damage
If your vehicle is damaged and requires sheet metal
repair or replacement, make sure the body repair shop
applies anti
-corrosion material to the parts repaired or
replaced to restore corrosion protection.
Original manufacturer replacement parts will provide
the corrosion protection while maintaining the warranty.

6-73 Vehicle Dimensions*
Wheelbase
Reg Cab Short Box 108.3 inches (275.1 cm). . . . . .
Reg Cab Long Box 117.9 inches (299.5 cm). . . . . .
Extended Cab 122.9 inches (312.2 cm). . . . . . . . . .
Crew Cab 122.9 inches (312.2 cm). . . . . . . . . . . . . .
Length
Reg Cab Short Box 189.0 inches (480.1 cm). . . . . .
Reg Cab Long Box 204.9 inches (520.4 cm). . . . . .
Extended Cab 203.6 inches (517.1 cm). . . . . . . . . .
Crew Cab 202.8 inches (515.0 cm). . . . . . . . . . . . . .
Height
2WD Reg Cab 62.1 inches (157.7 cm). . . . . . . . . . .
2WD Ext Cab 62.2 inches (158.0 cm). . . . . . . . . . .
4WD Reg Cab Short Box 63.8 inches (162.1 cm). .
4WD Reg Cab Long Box 65.4 inches (166.1 cm). .
4WD Extended Cab 63.8 inches (162.1 cm). . . . . .
4WD Crew Cab 67.6 inches (171.7 cm). . . . . . . . . .
Width67.9 inches (172.5 cm) . . . . . . . . . . . . . . . . . . Front Tread
2WD
0.0 Wheel Offset 54.5 inches (138.4 cm). . . . . . . . .
-6.4 Wheel Offset 55.0 inches (139.6 cm). . . . . . . .
4WD
15
-inch Tires 57.3 inches (145.4 cm). . . . . . . . . . . .
31 x 10.5 Tires 61.2 inches (155.4 cm). . . . . . . . . . .
Rear Tread
2WD 54.7 inches (138.8 cm). . . . . . . . . . . . . . . . . . . .
4WD
15
-inch Tires 55.1 inches (139.9 cm). . . . . . . . . . . .
31 x 10.5 Tires 59.1 inches (150.0 cm). . . . . . . . . . .
*Figures reflect base equipment only.

Short Trip/City Scheduled Maintenance
7-9
3,000 Miles (5 000 km)

Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.

Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)

Check rear/front axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking. (See footnote **.)
6,000 Miles (10 000 km)

Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.

Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)

Check rear/front axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking. (See footnote **.)

Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE

Short Trip/City Scheduled Maintenance
7-10
9,000 Miles (15 000 km)

Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.

Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)

Check rear/front axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking. (See footnote **.)
12,000 Miles (20 000 km)

Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.

Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)

Check rear/front axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking. (See footnote **.)

Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE