2009 SATURN ASTRA Owners Manual

Low-Prole Tires
If the vehicle has 225/40ZR18 or
215/45R18 size tires, they
are classied as low-prole
performance tires. These tires
are designed for very responsive
driving on wet or dry pavement.
You may also notice more
road noise with low-prole
performance tires and that they
tend to wear faster.
Notice:If the vehicle has
low-prole tires, they are more
susceptible to damage from
road hazards or curb impact
than standard prole tires.
Tire and/or wheel assembly
damage can occur when
coming into contact with road
hazards like, potholes, or
sharp edged objects, or when
sliding into a curb. The vehicle
warranty does not cover this
type of damage. Keep tires
set to the correct inationpressure and, when possible
avoid contact with curbs,
potholes, and other road
hazards.
Winter Tires
If the vehicle has 225/40ZR18 or
215/45R18 size tires, they are
classied as low-prole performance
tires. These tires are designed for
very responsive driving on wet or dry
pavement. If you expect to drive
on snow or ice covered roads often,
you may want to get winter tires
for your vehicle. All season tires
provide good overall performance on
most surfaces but they may not
offer the traction you would like or
the same level of performance
as winter tires on snow or ice
covered roads.
Winter tires, in general, are
designed for increased traction
on snow and ice covered roads.With winter tires, there may be
decreased dry road traction,
increased road noise, and shorter
tire tread life. After switching to
winter tires, be alert for changes in
vehicle handling and braking.
See your dealer/retailer for details
regarding winter tire availability
and proper tire selection. Also, see
Buying New Tires on page 9-54.
If you choose to use winter tires:
Use tires of the same brand and
tread type on all four wheel
positions.
Use only radial ply tires of the
same size, load range, and
speed rating as your original
equipment tires.
Winter tires with the same speed
rating as the original equipment tires
may not be available for H, V, W,
Y and ZR speed rated tires.
If you choose winter tires with a
lower speed rating, never exceed
the tire’s maximum speed capability.
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Tire Sidewall Labeling
Useful information about a tire
is molded into its sidewall.
The examples below show a
typical passenger vehicle tire and
a compact spare tire sidewall.
(A) Tire Size
:The tire size is
a combination of letters and
numbers used to dene 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) TPC Spec (Tire
Performance Criteria
Specication)
:Original
equipment tires designed to
GM’s specic tire performance
criteria have a TPC specication
code molded onto the sidewall.
GM’s TPC specications meet
or exceed all federal safety
guidelines.
(C) DOT (Department of
Transportation)
: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 (Department
of Transportation) code is the
Tire Identication 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
seeUniform Tire Quality
Grading on page 9-57.
(G) Maximum Cold Ination
Load Limit
:Maximum load
that can be carried and
the maximum pressure needed
to support that load.
Passenger (P-Metric) Tire
Example
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(A) Tire Ply Material:The type
of cord and number of plies in the
sidewall and under the tread.
(B) 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 50 mph
(80 km/h). The compact spare
tire is for emergency use when a
regular road tire has lost air
and gone at. If your vehicle
has a compact spare tire.SeeCompact Spare Tire on
page 9-68andIf a Tire
Goes Flat on page 9-60.
(C) Tire Identication Number
(TIN)
:The letters and numbers
following the DOT (Department
of Transportation) code is
the Tire Identication 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.
(E) Tire Ination
:The temporary
use tire or compact spare tire
should be inated to 60 psi
(420 kPa). For more information
on tire pressure and ination
seeInflation - Tire Pressure on
page 9-47.(F) Tire Size
:A combination of
letters and numbers dene a
tire’s width, height, aspect ratio,
construction type, and service
description. The letter T as
the rst character in the tire size
means the tire is for temporary
use only.
(G) TPC Spec (Tire
Performance Criteria
Specication)
:Original
equipment tires designed to
GM’s specic tire performance
criteria have a TPC specication
code molded onto the sidewall.
GM’s TPC specications meet
or exceed all federal safety
guidelines.
Compact Spare Tire Example
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Tire Size
The following illustration shows
an example of a typical
passenger vehicle tire size.
(A) Passenger (P-Metric) Tire
:The United States version of
a metric tire sizing system.
The letter P as the rst
character in the tire size
means a passenger vehicle tire
engineered to standards set
by the U.S. Tire and Rim
Association.
(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 index and speed rating
of the tire. The load index
represents the load carry
capacity a tire is certied to
carry. The speed rating is the
maximum speed a tire is certied
to carry a load.
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, 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.
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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.
SeeInflation - Tire Pressure on
page 9-47.
Curb Weight
: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 Identication
Number (TIN), an alphanumeric
designator which can also
identify the tire manufacturer,
production plant, brand, and date
of production.
GVWR
:Gross Vehicle Weight
Rating. SeeLoading the Vehicle
on page 8-30.
GAWR FRT
:Gross Axle
Weight Rating for the front axle.
SeeLoading the Vehicle on
page 8-30.
GAWR RR
:Gross Axle
Weight Rating for the rear axle.
SeeLoading the Vehicle on
page 8-30.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 can be
inated. The maximum air
pressure is molded onto the
sidewall.
Maximum Load Rating
:The load rating for a tire at the
maximum permissible ination
pressure for that tire.
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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 lbs (68 kg).
SeeLoading the Vehicle
on page 8-30.
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 Ination
Pressure
:Vehicle
manufacturer’s recommended
tire ination pressure as
shown on the tire placard.
SeeInflation - Tire Pressure
on page 9-47andLoading the
Vehicle on page 8-30.
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 9-54.
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 9-57.
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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
the Vehicle on page 8-30.
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 ination
pressure. See “Tire and Loading
Information Label” under
Loading the Vehicle on
page 8-30.
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 hazardsA vehicle specic Tire and
Loading Information label is
attached to your vehicle.
This label shows your vehicle’s
original equipment tires and
the correct ination pressures for
your tires when they are cold.
The recommended cold tire
ination 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, seeLoading
the Vehicle on page 8-30.
How you load your vehicle
affects vehicle handling and ride
comfort. Never load your
vehicle with more weight than it
was designed to carry.
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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 9-68.
How to Check
Use a good quality pocket-type
gage to check tire pressure.
You cannot tell if your tires are
properly inated simply by
looking at them. Radial tires
may look properly inated even
when they are under-inated.
Check the tire’s ination
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 ination pressure
matches the recommended
pressure on the Tire and
Loading Information label, no
further adjustment is necessary.
If the ination pressure is low,
add air until you reach the
recommended amount.
If you overll 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.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 ination 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 ination pressure
for the vehicle load.
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