2007 SATURN RELAY tire pressure
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(B) Tire Width:The three-digit number indicates
the tire section width in millimeters from sidewall
to sidewall.
(C) Aspect Ratio:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is
60, as shown in item C of the illustration, it would
mean that the tire’s sidewall is 60 percent as
high as it is wide.
(D) Construction Code:A letter code is used
to indicate the type of ply construction in the tire.
The letter R means radial ply construction; the
letter D means diagonal or bias ply construction;
and the letter B means belted-bias ply
construction.
(E) Rim Diameter:Diameter of the wheel in
inches.
(F) Service Description:These characters
represent the load range and speed rating of the
tire. The load index represents the load carry
capacity a tire is certi ed to carry. The load index
can range from 1 to 279. The speed rating is
the maximum speed a tire is certi ed to carry
a load. Speed ratings range from A to Z.Tire Terminology and De nitions
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.
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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. SeeIn ation - Tire Pressure on
page 469.
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 Identi cation Number (TIN),
an alphanumeric designator which can also identify
the tire manufacturer, production plant, brand,
and date of production.
GVWR:Gross Vehicle Weight Rating. See
Loading Your Vehicle on page 391.
GAWR FRT:Gross Axle Weight Rating for the
front axle. SeeLoading Your Vehicle on page 391.
GAWR RR:Gross Axle Weight Rating for the
rear axle. SeeLoading Your Vehicle on page 391.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 In ation Pressure:The maximum
air pressure to which a cold tire may be in ated.
The maximum air pressure is molded onto the
sidewall.
Maximum Load Rating:The load rating for a tire
at the maximum permissible in ation pressure
for that tire.
Maximum Loaded Vehicle Weight:The sum of
curb weight, accessory weight, vehicle capacity
weight, and production options weight.
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Normal Occupant Weight:The number of
occupants a vehicle is designed to seat multiplied
by 150 lbs (68 kg). SeeLoading Your Vehicle
on page 391.
Occupant Distribution:Designated seating
positions.
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 In ation Pressure:Vehicle
manufacturer’s recommended tire in ation
pressure as shown on the tire placard. See
In ation - Tire Pressure on page 469andLoading
Your Vehicle on page 391.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 473.
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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. See
Uniform Tire Quality Grading on page 477.
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 391.
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 in ation pressure. See “Tire
and Loading Information Label” underLoading
Your Vehicle on page 391.In ation - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-in ation or over-in ation is all right.
It is not. If your tires do not have enough air
(under-in ation), 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-in ation),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazards
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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 in ation
pressures for your tires when they are cold.
The recommended cold tire in ation 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 391. 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. Do not
forget to check the compact spare tire, it should be
at 60 psi (420 kPa). For additional information
regarding the compact spare tire, seeCompact
Spare Tire on page 500.
How to Check
Use a good quality pocket-type gage to check
tire pressure. You cannot tell if your tires are
properly in ated simply by looking at them. Radial
tires may look properly in ated even when they
are under-in ated. Check the tire’s in ation
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 rmly onto the valve to
get a pressure measurement. If the cold tire
in ation pressure matches the recommended
pressure on the Tire and Loading Information
label, no further adjustment is necessary. If the
in ation pressure is low, add air until you reach
the recommended amount.
If you over ll the tire, release air by pushing on
the metal stem in the center of the tire valve.
Re-check 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.
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High-Speed Operation
{CAUTION:
Driving at high speeds, 100 mph (160 km/h)
or higher, puts an additional strain on tires.
Sustained high-speed driving causes
excessive heat build up and can cause
sudden tire failure. You could have a
crash and you or others could be killed.
Some high-speed rated tires require
in ation pressure adjustment for high
speed operation. When speed limits and
road conditions are such that a vehicle
can be driven at high speeds, make sure
the tires are rated for high speed operation,
in excellent condition, and set to the
correct cold tire in ation pressure for the
vehicle load.If your vehicle has P225/60R17 size tires,
they will require in ation pressure adjustment
when driving your vehicle at speeds of
100 mph (160 km/h) or higher. Set the cold
in ation pressure to the maximum in ation
pressure shown on the tire sidewall, or
38 psi (262 kPa), whichever is lower. See the
example following. When you end this high-speed
driving, return the tires to the cold tire in ation
pressure shown on the Tire and Loading
Information label. SeeLoading Your Vehicle
on page 391andIn ation - Tire Pressure
on page 469.
Example:
You will nd the maximum load and in ation
pressure molded on the tire’s sidewall, in small
letters, near the rim ange. It will read something
like this: Maximum load 690 kg (1521 lbs)
300 kPa (44 psi) Max. Press.
For this example, you would set the
in ation pressure for high-speed driving at
38 psi (262 kPa).
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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 473
andWheel Replacement on page 478for
more information.
The purpose of regular rotation is to achieve
more uniform wear for all tires on the vehicle.
The rst rotation is the most important. See
Scheduled Maintenance on page 522.When rotating your tires, always use the correct
rotation pattern shown here.
Do not include the compact spare tire in your tire
rotation.
After the tires have been rotated, adjust the front
and rear in ation pressures as shown on the
Tire and Loading Information label.
Make certain that all wheel nuts are properly
tightened. See “Wheel Nut Torque” under
Capacities and Speci cations on page 518.
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Buying New Tires
GM has developed and matched speci c tires
for your vehicle. The original equipment tires
installed on your vehicle, when it was new,
were designed to meet General Motors Tire
Performance Criteria Speci cation (TPC spec)
system rating. If you need replacement tires,
GM strongly recommends that you get tires with
the same TPC Spec rating. This way, your vehicle
will continue to have tires that are designed to
give the same performance and vehicle safety,
during normal use, as the original tires.GM’s exclusive TPC Spec system considers over
a dozen critical speci cations that impact the
overall performance of your vehicle, including
brake system performance, ride and handling,
traction control, and tire pressure monitoring
performance. GM’s TPC Spec number is molded
onto the tire’s sidewall by the tire manufacturer.
If the tires have an all-season tread design,
the TPC spec number will be followed by an
MS for mud and snow. SeeTire Sidewall Labeling
on page 463for additional information.
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