2004 Oldsmobile Silhouette tire pressure

(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 In¯ation Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For information on
recommended tire pressure see
In¯ation - Tire Pressure
on page 5-67andLoading Your Vehicle on page 4-33.
LT-Metric Tire
5-60

(A) Tire Size:The tire size code is a combination of
letters and numbers used to de®ne a particular
tire's width, height, aspect ratio, construction type and
service description. See the ªTire Sizeº illustration
later in this section for more detail.
(B) Tire Performance Criteria Speci®cation
(TPC Spec):Original equipment tires designed to
GM's speci®c tire performance criteria have a TPC
speci®cation code molded onto the sidewall. GM's
TPC speci®cations 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 con®guration.
For information on recommended tire pressure see
In¯ation - Tire Pressure on page 5-67andLoading
Your Vehicle on page 4-33.
(D) 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.(E) Tire Identi®cation Number (TIN):The letters and
numbers following DOT code are the Tire Identi®cation
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.
(F) Tire Ply Material:The type of cord and number
of plies in the sidewall and under the tread.
(G) Single Tire Maximum Load:Maximum load that
can be carried and the maximum pressure needed to
support that load when used as a single. For information
on recommended tire pressure see
In¯ation - Tire
Pressure on page 5-67andLoading Your Vehicle
on page 4-33.
5-61

(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 ¯at. See
Compact Spare Tire on
page 5-91andIf a Tire Goes Flat on page 5-76.
(B) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(C) Tire Identi®cation Number (TIN):The Tire
Identi®cation 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 In¯ation Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. See
Compact Spare Tire
on page 5-91andLoading Your Vehicle on page 4-33.
(E) Tire In¯ation:The temporary use tire or compact
spare tire should be in¯ated to 60 psi (420 kPa).
For more information on tire pressure and in¯ation see
In¯ation - Tire Pressure on page 5-67.
Compact Spare Tire Example
5-62

(A) Light Truck (LT-Metric) Tire:The United States
version of a metric tire sizing system. The letter ªLTº
as the ®rst two characters in the tire size means a light
truck 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 ª75,º as shown in item ªCº
of the illustration, it would mean that the tire's sidewall
is 75% 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
ªRº means radial ply construction; the letter ªDº means
diagonal or bias ply construction; and the letter ªBº
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a tire.
The load index can range from 1 to 279. Speed ratings
range from ªAº to ªZº. The light truck tire size example
above shows dual or single tire con®gurations.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, power steering,
power brakes, power windows, power seats, and air
conditioning.
Aspect Ratio:The relationship of a tire's height to
its width. Light Truck (LT-Metric) Tire
5-64

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 In¯ation 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. See
In¯ation - Tire Pressure on page 5-67.
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 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 4-33.
GAWR FRT:Gross Axle Weight Rating for the front
axle, see
Loading Your Vehicle on page 4-33.
GAWR RR:Gross Axle Weight Rating for the rear axle,
see
Loading Your Vehicle on page 4-33.
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.
There are 6.9 kPa's to one psi.
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.
5-65

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). See
Loading Your Vehicle on page 4-33.
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 In¯ation Pressure:Vehicle
manufacturer's recommended tire in¯ation pressure and
shown on the tire placard. See
In¯ation - Tire Pressure
on page 5-67andLoading Your Vehicle on page 4-33.
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 ªwear bars,º that show across the tread of a tire
when only 2/32 inch of tread remains. See
When It
Is Time for New Tires on page 5-70.
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 5-71.
5-66

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 4-33.
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 in¯ation pressure. See
Loading
Your Vehicle on page 4-33.
In¯ation - Tire Pressure
The Certi®cation/Tire label or Tire and Loading
Information label shows the correct in¯ation pressures
for your tires when they're cold. ªColdº 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 4-33.
Notice:Don't let anyone tell you that underin¯ation
or overin¯ation is all right. It's not. If your tires
don't have enough air (underin¯ation), 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 (overin¯ation),
you can get the following:
·Unusual wear
·Bad handling
·Rough ride
·Needless damage from road hazards
5-67

When to Check
Check your tires once a month or more.
Also, check the tire pressure of the 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 in¯ated
simply by looking at them. Radial tires may look
properly in¯ated even when they're underin¯ated.
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 is low,
add air until you reach the recommended pressure
on the Certi®cation/Tire label or the Tire and Loading
Information label.
If you over®ll 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. See
When It Is Time
for New Tires on page 5-70andWheel Replacement
on page 5-73for more information.
Make sure the spare tire is stored securely. Push, pull
and then try to rotate or turn the tire. If the tire moves,
use the folding wrench to tighten the cable. See ªStoring
the Spare Tire and Toolsº under
Changing a Flat Tire on
page 5-76.
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 6-4.
5-68