2007 CADILLAC STS Owners Manual

(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 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 seeInation - Tire Pressure on
page 431.
(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.
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.
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(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 certied to carry. The load index
can range from 1 to 279. The speed rating is
the maximum speed a tire is certied to carry a
load. Speed ratings range from A to Z.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.
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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. SeeInation - Tire Pressure
on page 431.
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 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. See
Loading Your Vehicle on page 349.
GAWR FRT:Gross Axle Weight Rating for the
front axle. SeeLoading Your Vehicle on page 349.GAWR RR:Gross Axle Weight Rating for the rear
axle. SeeLoading Your Vehicle on page 349.
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 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 Your Vehicle
on page 349.
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. See
Ination - Tire Pressure on page 431andLoading
Your Vehicle on page 349.
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.
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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 440.
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 444.
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 349.
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” underLoading
Your Vehicle on page 349.Run-Flat Tires (STS-V)
If your vehicle has run-at tires, there is no spare
tire and no tire changing equipment. Your
vehicle also has a Tire Pressure Monitor
System (TPMS) which will alert you if there is a
loss of tire pressure in any of the tires. See
Tire Pressure Monitor System on page 433.
{CAUTION:
When the low tire warning light is
displayed on the instrument panel cluster,
your vehicle’s handling capabilities will be
reduced during severe maneuvers. If you
drive too fast, you could lose control of
your vehicle. You or others could be
injured. Do not drive over 55 mph
(90 km/h) when the low tire warning light
is displayed. Drive cautiously and check
your tire pressures as soon as you can.
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If a tire goes at, you will not need to stop on the
side of the road to change the tire. You can
just keep on driving. The vehicle’s run-at tires
can operate effectively with no air pressure for up
to 50 miles (80 km) at speeds up to 55 mph
(90 km/h). The shorter the distance you drive and
the slower the speed, the greater the chance
that the tire will not have to be replaced. When a
tire is lled with air, it provides a cushion
between the road and the wheel. Because you will
not have this cushion when driving on a deated
run-at tire, try to avoid potholes that could
damage your wheel and require replacement of it.
Some road hazards can damage a tire beyond
repair. This damage could occur even before you
have driven on the tire in a deated condition.
When a tire has been damaged, or if you have
driven any distance on a deated run-at tire, check
with an authorized run-at tire service center, as
soon as possible, to determine whether the tire can
be repaired or should be replaced. To maintain your
vehicle’s run-at feature, all replacement tires must
be self-supporting tires. To locate the nearest GM
or authorized run-at servicing facility, call
Roadside Service. SeeRoadside Service on
page 531for details.
{CAUTION:
Run-at tires are constructed differently
than other tires and could explode during
improper service. You or others could be
injured or killed if you attempt to repair,
replace, dismount, or mount a run-at tire.
Let only an authorized run-at service
center repair, replace, dismount, and
mount run-at tires.
The valve stems on your vehicle’s run-at tires
have sensors that are part of the Tire Pressure
Monitor System (TPMS). These sensors contain
batteries which are designed to last for 10 years
under normal driving conditions. See your GM
dealer, if the TPMS sensors or a wheel ever need
replacement.
Notice:Using liquid sealants can damage the
tire valves and tire pressure monitor sensors in
your vehicle’s run-at tires. This damage would
not be covered by warranty. Do not use liquid
sealants in your vehicle’s run-at tires.
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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 Tire and Loading Information label is attached to
the vehicle’s center pillar, below the driver’s
door latch. This label lists your vehicle’s original
equipment tires and shows 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, see
Loading Your Vehicle on page 349. 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, if your
vehicle has one. The compact spare should be at
60 psi (420 kPa). For additional information
regarding the compact spare tire, seeCompact
Spare Tire on page 475.
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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 underinated. 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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