2004 GMC SONOMA tires

Brake Wear
Your vehicle has four-wheel disc brakes.
Disc brake pads have built-in wear indicators that make
a high-pitched warning sound when the brake pads
are worn and new pads are needed. The sound
may come and go or be heard all the time your vehicle
is moving (except when you are pushing on the
brake pedal firmly).
{CAUTION:
The brake wear warning sound means that
soon your brakes will not work well. That
could lead to an accident. When you hear the
brake wear warning sound, have your vehicle
serviced.
Notice:Continuing to drive with worn-out brake
pads could result in costly brake repair.Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in
the proper sequence to GM torque specifications.
Brake linings should always be replaced as complete
axle sets.
SeeBrake System Inspection on page 6-31.Brake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in
pedal travel. This could be a sign of brake trouble.
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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. For additional
information refer to the tire manufacturer’s booklet
included with your vehicle’s Owner’s Manual.
{CAUTION:
Poorly maintained and improperly used tires
are dangerous.
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.
CAUTION: (Continued)
CAUTION: (Continued)

Underinated 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.
Overinated 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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(A) Tire Size Code:The tire size code is a combination
of letters and numbers used to define a particular
tire’s width, height, aspect ratio, construction type and
service description. See the “Tire Size Code” illustration
later in this section for more detail.
(B) Tire Performance Criteria Specication (TPC
Spec):Original equipment tires designed to GM’s
specific tire performance criteria have a TPC
specification code molded onto the sidewall. GM’s TPC
specifications meet or exceed all federal safety
guidelines.
(C) Department of Transportation (DOT):The
Department of Transportation (DOT) code indicates that
the tire is in compliance with the U.S. Department of
Transportation Motor Vehicle Safety Standards.(D) Tire Identication Number (TIN):The letters and
numbers following DOT code are the Tire Identification
Number (TIN). The TIN shows the manufacturer
and plant code, tire size, and date the tire was
manufactured. The TIN is molded onto both sides of the
tire, although only one side may have the date of
manufacture.
(E) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(F) Uniform Tire Quality Grading (UTQG):Tire
manufacturers are required to grade tires based on three
performance factors: treadwear, traction and
temperature resistance. For more information, see
Uniform Tire Quality Grading on page 5-71.
(G) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For information on
recommended tire pressure seeInation - Tire Pressure
on page 5-67andLoading Your Vehicle on page 4-45.
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(A) Tire Size:The tire size code is a combination of
letters and numbers used to define a particular
tire’s width, height, aspect ratio, construction type and
service description. See the “Tire Size” illustration
later in this section for more detail.
(B) Tire Performance Criteria Specication (TPC
Spec):Original equipment tires designed to GM’s
specific tire performance criteria have a TPC
specification code molded onto the sidewall. GM’s TPC
specifications meet or exceed all federal safety
guidelines.
(C) Dual Tire Maximum Load:Maximum load that can
be carried and the maximum pressure needed to
support that load when used in a dual configuration. For
information on recommended tire pressure see
Ination - Tire Pressure on page 5-67andLoading Your
Vehicle on page 4-45.
LT-Metric Tire
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(A) Temporary Use Only:The compact spare tire or
temporary use tire has a tread life of approximately
3,000 miles (5 000 km) and should not be driven
at speeds over 65 mph (105 km/h). The compact spare
tire is for emergency use when a regular road tire
has lost air and gone flat. SeeCompact Spare Tire on
page 5-85andIf a Tire Goes Flat on page 5-74.
(B) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(C) Tire Identication Number (TIN):The Tire
Identification Number (TIN). The TIN shows the
manufacturer and plant code, tire size, and date the tire
was manufactured. The TIN is molded onto both
sides of the tire, although only one side may have the
date of manufacture.
(D) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. SeeCompact Spare Tire
on page 5-85andLoading Your Vehicle on page 4-45.(E) Tire Ination:The temporary use tire or compact
spare tire should be inflated to 60 psi (420 kPa).
For more information on tire pressure and inflation see
Ination - Tire Pressure on page 5-67.
(F) Tire Size:A combination of letters and numbers
define a tire’s width, height, aspect ratio, construction
type and service description. The letter “T” as the
first character in the tire size means the tire is for
temporary use only.
(G) Tire Performance Criteria Specication (TPC
Spec):Original equipment tires designed to GM’s
specific tire performance criteria have a TPC
specification code molded onto the sidewall. GM’s TPC
specifications meet or exceed all federal safety
guidelines.
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Maximum Loaded Vehicle Weight:The sum of curb
weight; accessory weight; vehicle capacity weight;
and production options weight.
Normal Occupant Weight:The number of occupants a
vehicle is designed to seat multiplied by 150 pounds
(68 kg). SeeLoading Your Vehicle on page 4-45.
Occupant Distribution:Designated seating positions.
Outward Facing Sidewall:The side of a asymmetrical
tire that has a particular side that faces outward
when mounted on a vehicle. The side of the tire that
contains a whitewall, bears white lettering or bears
manufacturer, brand and or model name molding that is
higher or deeper than the same moldings on the
other sidewall of the tire.
Passenger (P-Metric) Tire:A tire used on passenger
cars and some light duty trucks and multipurpose
vehicles.
Recommended Ination Pressure:Vehicle
manufacturer’s recommended tire inflation pressure and
shown on the tire placard. SeeInation - Tire Pressure
on page 5-67andLoading Your Vehicle on page 4-45.
Radial Ply tire:A pneumatic tire in which the ply cords
that extend to the beads are laid at 90 degrees to the
centerline of the tread.Rim:A metal support for a tire and upon which the tire
beads are seated.
Sidewall:The portion of a tire between the tread and
the bead.
Speed Rating:An alphanumeric code assigned to a
tire indicating the maximum speed at which a tire
can operate.
Traction:The friction between the tire and the road
surface. The amount of grip provided.
Tread:The portion of a tire that comes into contact
with the road.
Treadwear Indicators:Narrow bands, sometimes
called “wear bars,” that show across the tread of a tire
when only 2/32 inch of tread remains. SeeWhen It
Is Time for New Tires on page 5-69.
UTQGS:Uniform Tire Quality Grading Standards, a tire
information system that provides consumers with
ratings for a tire’s traction, temperature and treadwear.
Ratings are determined by tire manufacturers using
government testing procedures. The ratings are molded
into the sidewall of the tire. SeeUniform Tire Quality
Grading on page 5-71.
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Vehicle Capacity Weight:The number of designated
seating positions multiplied by 150 lbs. (68 kg) plus
the rated cargo load. SeeLoading Your Vehicle
on page 4-45.
Vehicle Maximum Load on the Tire:Load on an
individual tire due to curb weight, accessory weight,
occupant weight and cargo weight.
Vehicle Placard:A label permanently attached to a
vehicle showing the original equipment tire size
and recommended inflation pressure. SeeLoading Your
Vehicle on page 4-45.
Ination - Tire Pressure
The tire and loading information label, 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 km). See
Loading Your Vehicle on page 4-45, for the location
of your vehicle’s tire and loading information label.
Notice:Don’t let anyone tell you that underination
or overination is all right. It’s not. If your tires
don’t have enough air (underination), you can get
the following:
Too much exing
Too much heat
Tire overloading
Bad wear
Bad handling
Bad fuel economy
If your tires have too much air (overination), you
can get the following:
Unusual wear
Bad handling
Rough ride
Needless damage from road hazards
When to Check
Check your tires once a month or more.
Also, check the tire pressure of the spare tire.
If you have a compact spare tire, it should be at
60 psi (420 kPa).
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. 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).
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remove the valve cap from the tire valve stem. Press
the tire gage 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 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 gage.
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 5,000 to 8,000 miles
(8 000 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. SeeWhen It Is Time
for New Tires on page 5-69andWheel Replacement
on page 5-72for more information.Make sure the spare tire is stored securely. Push, pull,
and then try to rotate or turn the tire. If it moves,
use the wheel wrench to tighten the cable. See
Changing a Flat Tire on page 5-75.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The first rotation
is the most important. SeePart A: Scheduled
Maintenance Services on page 6-4, for scheduled
rotation intervals.
When rotating your tires, always use the correct rotation
pattern shown here.
If your vehicle has a compact spare tire or a spare tire
that does not match your vehicle’s road tires and
wheels, in size and type, do not include the spare in the
tire rotation.
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