
Black plate (50,1)Cadillac STS Owner Manual - 2011
Tires
Your new vehicle comes with high-quality tires
made by a leading tire manufacturer. If you ever
have questions about your tire warranty and
where to obtain service, see your vehicle
Warranty booklet for details. For additional
information refer to the tire manufacturer.
{WARNING:
.Poorly maintained and improperly used tires
are dangerous.
.Overloading your tires can cause overheating
as a result of too much flexing. You could
have a blowout and a serious accident. See
Loading the Vehicle on page 5‑23.
.Under inflated tires pose the same danger as
overloaded tires. The resulting crash could
cause serious injury. Check all tires frequently
to maintain the recommended pressure. Tire
pressure should be checked when your tires
are cold.(Continued)
WARNING: (Continued)
.Over inflated tires are more likely to be
cut, punctured, or broken by a sudden
impact—such as when you hit a pothole.
Keep tires at the recommended pressure.
.Worn or old tires can cause a crash. If your
tread is badly worn, replace them.
.Replace any tires that have been damaged by
impacts with potholes, curbs, etc.
.Improperly repaired tires can cause a crash.
Only your dealer or an authorized tire service
center should repair, replace, dismount, and
mount the tires.
.Do not spin the tires in excess of 55 km/h
(35 mph) on slippery surfaces such as snow,
mud, ice, etc. Excessive spinning may cause
the tires to explode.
See High-Speed Operation
on page 6‑60for inflation
pressure adjustment for high speed driving.
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Black plate (52,1)Cadillac STS Owner Manual - 2011
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.
Passenger (P‐Metric) Tire Example
(A) Tire Size:The tire size is a combination of
letters and numbers used to define 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
Specification)
:Original equipment tires designed
to GM's specific tire performance criteria have a
TPC specification code molded onto the sidewall.
GM's TPC specifications 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 Identification Number (TIN)
:The letters
and numbers following DOT (Department of
Transportation) code is the Tire Identification
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.
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Black plate (54,1)Cadillac STS Owner Manual - 2011
(B) Tire Ply Material:The type of cord and
number of plies in the sidewall and under the
tread.
(C) Tire Identification Number (TIN)
:The letters
and numbers following the DOT (Department of
Transportation) code is the Tire Identification
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 Inflation Load Limit
:
Maximum load that can be carried and the
maximum pressure needed to support that load.
(E) Tire Inflation
:The temporary use tire or
compact spare tire should be inflated to 60 psi
(420 kPa). For more information on tire pressure
and inflation see Inflation - Tire Pressure
on
page 6‑58
.
(F) Tire Size
:A combination of letters and
numbers define a tire's width, height, aspect ratio,
construction type, and service description. The
letter T as the first character in the tire size means
the tire is for temporary use only. (G) TPC Spec (Tire Performance Criteria
Specification)
:Original equipment tires designed
to GM's specific tire performance criteria have a
TPC specification code molded onto the sidewall.
GM's TPC specifications 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 first character in the tire size means a
passenger vehicle tire engineered to standards
set by the U.S. Tire and Rim Association.
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Black plate (55,1)Cadillac STS Owner Manual - 2011
(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 carrying
capacity a tire is certified to carry. The speed
rating is the maximum speed a tire is certified to
carry a load.
Tire Terminology and Definitions
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.
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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Black plate (63,1)Cadillac STS Owner Manual - 2011
Factory-installed Tire Inflator Kits use a GM approved
liquid tire sealant. Using non-approved tire sealants
could damage the TPMS sensors. SeeTire Sealant and
Compressor Kit (Without Selector Switch)
on
page 6‑76or Tire Sealant and Compressor Kit (With
Selector Switch)on page 6‑85for information
regarding the inflator kit materials and instructions.
TPMS Malfunction Light and Message
The TPMS will not function properly if one or more of
the TPMS sensors are missing or inoperable. When the
system detects a malfunction, the low tire warning light
flashes for about one minute and then stays on for the
remainder of the ignition cycle. A DIC warning message
is also displayed. The low tire warning light and DIC
warning message come on at each ignition cycle until
the problem is corrected. Some of the conditions that
can cause the malfunction light and DIC message to
come on are:
.One of the road tires has been replaced with the
spare tire, if the vehicle has one. The spare tire
does not have a TPMS sensor. The DIC message
should go off once you re‐install the road tire
containing the TPMS sensor.
.The TPMS sensor matching process was started
but not completed or not completed successfully
after rotating the vehicle's tires. The DIC message
and TPMS malfunction light should go off once the
TPMS sensor matching process is performed
successfully. See “TPMS Sensor Matching
Process” later in this section.
.One or more TPMS sensors are missing or
damaged. The DIC message and the TPMS
malfunction light should go off when the TPMS
sensors are installed and the sensor matching
process is performed successfully. See your dealer
for service.
.Replacement tires or wheels do not match your
vehicle's original equipment tires or wheels. Tires
and wheels other than those recommended for
your vehicle could prevent the TPMS from
functioning properly. See Buying New Tires
on
page 6‑67.
.Operating electronic devices or being near facilities
using radio wave frequencies similar to the TPMS
could cause the TPMS sensors to malfunction.
If the TPMS is not functioning it cannot detect or signal
a low tire condition. See your dealer for service if the
TPMS malfunction light and DIC message comes on
and stays on.
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Black plate (64,1)Cadillac STS Owner Manual - 2011
TPMS Sensor Matching Process
Each TPMS sensor has a unique identification code.
Any time you replace one or more of the TPMS sensors
or rotate your vehicle's tires, the identification codes will
need to be matched to the new tire/wheel position. The
sensors are matched to the tire/wheel positions in the
following order: driver side front tire, passenger side
front tire, passenger side rear tire, and driver side rear
tire using a TPMS diagnostic tool. See your dealer for
service.
The TPMS sensors may also be matched to each tire/
wheel position by increasing or decreasing the tire's air
pressure. When increasing the tire's pressure, do not
exceed the maximum inflation pressure indicated on the
tire's sidewall. If using this method to match TPMS
sensors, the complete procedure outlined below must
be performed within 15 minutes of the vehicle being
stationary.
To decrease air-pressure out of a tire you can use the
pointed end of the valve cap, a pencil-style air pressure
gauge, or a key.
You will have one minute to match the first tire/wheel
position, and five minutes overall, to match all four
tire/wheel positions. If it takes longer than one minute to
match the first tire and wheel, or more than five minutes
to match all four tire/wheel positions, the matching
process stops and you will need to start over.The TPM matching process is outlined below:
1. Set the parking brake.
2. Press the push-button ignition switch to Acc.
3. Using the keyless access transmitter, lock and unlock the vehicle's doors.
4. Press the lock and unlock buttons, at the same time, on the keyless access transmitter. The horn
sounds twice, indicating that the TPMS is ready,
and the sensor matching process can begin.
5. Start with the driver side front tire.
6. Remove the valve cap from the valve stem. Activate the TPMS sensor by increasing or
decreasing the tire's air pressure for five seconds,
or until a horn chirp sounds. The horn chirp, which
may take up to 30 seconds to sound, confirms that
the sensor identification code has been matched to
this tire position.
7. Proceed to the passenger side front tire, and repeat the procedure in Step 6.
8. Proceed to the passenger side rear tire, and repeat the procedure in Step 6.
9. Proceed to the driver side rear tire, and repeat the procedure in Step 6.
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Black plate (68,1)Cadillac STS Owner Manual - 2011
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 specifications 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 near the tire size. 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 6‑52
for additional information.
GM recommends replacing tires in sets of four.
This is because uniform tread depth on all tires
will help keep your vehicle performing most like it
did when the tires were new. Replacing less than
a full set of tires can affect the braking and
handling performance of your vehicle.
{WARNING:
Tires could explode during improper service. You
or others could be injured or killed if you attempt
to mount or dismount a tire. Only your dealer or
an authorized tire service center should mount
and dismount the tires.
The optional 18‐inch performance tires, size
255/45ZR18 99Y, used on some vehicles, meets
the General Motors Tire Performance Criteria
Specification (TPC Spec) rating but the TPC Spec
code has not been molded onto the tire's sidewall.
If your vehicle has these tires, and you need to
replace them, you can still get these TPC Spec
rated tires by asking your GM dealer. Your GM
dealer can order these tires by part number. This
way, your vehicle will continue to give the proper
endurance, handling, traction, and ride as the
original tires.
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Black plate (71,1)Cadillac STS Owner Manual - 2011
Uniform Tire Quality Grading
Quality grades can be found where applicable on
the tire sidewall between tread shoulder and
maximum section width. For example:
Treadwear 200 Traction AA
Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration (NHTSA), which
grades tires by treadwear, traction, and
temperature performance. This applies only to
vehicles sold in the United States. The grades are
molded on the sidewalls of most passenger car
tires. The Uniform Tire Quality Grading (UTQG)
system does not apply to deep tread, winter-type
snow tires, space-saver, or temporary use spare
tires, tires with nominal rim diameters of
10 to 12 inches (25 to 30 cm), or to some
limited-production tires.
While the tires available on General Motors
passenger cars and light trucks may vary with
respect to these grades, they must also conform
to federal safety requirements and additional
General Motors Tire Performance Criteria (TPC)
standards.All Passenger Car Tires Must Conform to Federal
Safety Requirements In Addition To These
Grades.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
government test course. For example, a tire
graded 150 would wear one and a half (1½) times
as well on the government course as a tire graded
100. The relative performance of tires depends
upon the actual conditions of their use, however,
and may depart significantly from the norm due to
variations in driving habits, service practices and
differences in road characteristics and climate.
Traction
–AA, A, B, C
The traction grades, from highest to lowest,
are AA, A, B, and C. Those grades represent
the tire's ability to stop on wet pavement as
measured under controlled conditions on specified
government test surfaces of asphalt and concrete.
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