2007 GMC SAVANA Owner's Manual

Tire Terminology and Denitions
Air Pressure:The amount of air inside the tire
pressing outward on each square inch of the
tire. Air pressure is expressed in pounds
per square inch (psi) or kilopascal (kPa).
Accessory Weight:This means the combined
weight of optional accessories. Some examples of
optional accessories are, automatic
transmission/transaxle, power steering, power
brakes, power windows, power seats, and
air conditioning.
Aspect Ratio:The relationship of a tire’s height
to its width.
Belt:A rubber coated layer of cords that is
located between the plies and the tread. Cords
may be made from steel or other reinforcing
materials.
Bead:The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the rim.Bias Ply Tire:A pneumatic tire in which the plies
are laid at alternate angles less than 90 degrees
to the centerline of the tread.
Cold Tire Pressure:The amount of air pressure in
a tire, measured in pounds per square inch (psi) or
kilopascals (kPa) before a tire has built up heat
from driving. SeeInation - Tire Pressure on
page 348.
Curb Weight:This means the weight of a motor
vehicle with standard and optional equipment
including the maximum capacity of fuel, oil, and
coolant, but without passengers and cargo.
DOT Markings:A code molded into the sidewall
of a tire signifying that the tire is in compliance
with the U.S. Department of Transportation (DOT)
motor vehicle safety standards. The DOT code
includes the Tire Identification Number (TIN),
an alphanumeric designator which can also identify
the tire manufacturer, production plant, brand,
and date of production.
345

GVWR:Gross Vehicle Weight Rating. See
Loading Your Vehicle on page 259.
GAWR FRT:Gross Axle Weight Rating for the
front axle. SeeLoading Your Vehicle on page 259.
GAWR RR:Gross Axle Weight Rating for the
rear axle. SeeLoading Your Vehicle on page 259.
Intended Outboard Sidewall:The side of an
asymmetrical tire, that must always face outward
when mounted on a vehicle.
Kilopascal (kPa):The metric unit for air pressure.
Light Truck (LT-Metric) Tire:A tire used on
light duty trucks and some multipurpose passenger
vehicles.
Load Index:An assigned number ranging from
1 to 279 that corresponds to the load carrying
capacity of a tire.Maximum Ination Pressure:The maximum air
pressure to which a cold tire may be inflated.
The maximum air pressure is molded onto
the sidewall.
Maximum Load Rating:The load rating for a tire
at the maximum permissible inflation pressure
for that tire.
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 lbs (68 kg). SeeLoading Your Vehicle
on page 259.
Occupant Distribution:Designated seating
positions.
346

Outward Facing Sidewall:The side of an
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 as shown on the tire placard. See
Ination - Tire Pressure on page 348andLoading
Your Vehicle on page 259.
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 1/16 inch (1.6 mm) of tread
remains. SeeWhen It Is Time for New Tires on
page 353.
347

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 356.
Vehicle Capacity Weight:The number of
designated seating positions multiplied by
150 lbs (68 kg) plus the rated cargo load. See
Loading Your Vehicle on page 259.
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 vehicle’s capacity weight
and the original equipment tire size and
recommended inflation pressure. See “Tire and
Loading Information Label” underLoading
Your Vehicle on page 259.Ination - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-ination or over-ination is all right. It is
not. If your tires do not have enough air
(under-ination), you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air (over-ination),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazards
348

A Tire and Loading Information label is attached to
the vehicle’s center pillar (B-pillar), below the
driver’s door latch. This label shows your vehicle’s
original equipment tires and the correct inflation
pressures for your tires when they are cold.
The recommended cold tire inflation pressure,
shown on the label, is the minimum amount of air
pressure needed to support your vehicle’s
maximum load carrying capacity.
For additional information regarding how much
weight your vehicle can carry, and an example of
the tire and loading information label, see
Loading Your Vehicle on page 259. How you load
your vehicle affects vehicle handling and ride
comfort, never load your vehicle with more weight
than it was designed to carry.
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 cannot 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).
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.
349

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
wheel nut tightening information, see “Removing
the Flat Tire and Installing the Spare Tire” later in
this section, underChanging a Flat Tire on
page 360. Also see “Wheel Nut Torque” under
Capacities and Specications on page 393.
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. SeeTire Inspection and Rotation
on page 351. Also seeScheduled Maintenance
(Gasoline Engine) on page 399.{CAUTION:
If you operate your vehicle with a tire
that is badly underinated, the tire can
overheat. An overheated tire can lose air
suddenly or catch re. You or others could
be injured. Be sure all tires (including the
spare) are properly inated.
SeeTires on page 340andInation - Tire
Pressure on page 348for more information on
proper tire inflation.
350

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 353
andWheel Replacement on page 357for
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 ratchet/wheel wrench to tighten the
cable. SeeChanging a Flat Tire on page 360.
If your vehicle has dual rear wheels, also seeDual
Tire Operation on page 350.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The
first rotation is the most important. SeeScheduled
Maintenance (Gasoline Engine) on page 399.If your vehicle has single rear wheels, always use
the correct rotation patterns shown here when
rotating your vehicle’s tires. Do not include
the spare tire in the tire rotation, if the spare
tire/wheel assembly does not match your vehicle’s
road tires and wheels in size and type.
Single Rear Wheels
351

If your vehicle has dual rear wheels, always use
one of the correct rotation patterns shown
here when rotating your tires.
When you install dual wheels, be sure that 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
Tire and Loading Information label. SeeLoading
Your Vehicle on page 259. Make certain that
all wheel nuts are properly tightened. See “Wheel
Nut Torque” underCapacities and Specications
on page 393.
{CAUTION:
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
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 needed, to get all the rust or dirt
off. SeeChanging a Flat Tire on page 360.
Dual Rear Wheels
352