2004 CADILLAC XLR Owners Manual

A. Tire Size
B. Tire Performance Criteria Speci®cation (TPC Spec)
C. Department of Transportation (DOT)
D. Tire Identi®cation Number (TIN)
E. Tire Ply Material
F. Uniform Tire Quality Grading (UTQG)
G. Maximum Cold In¯ation Load Limit
(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 Size º 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) 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.
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(D) 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.
(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 see
Uniform Tire Quality Grading on page 5-64.
(G) Maximum Cold In¯ation Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For more information on
recommended tire pressure see
In¯ation - Tire Pressure
on page 5-57andLoading Your Vehicle on page 4-32.
Tire Size Codes
The following illustration shows an example of a typical
passenger car tire size.
A. P-Metric Tire
B. Tire Width
C. Aspect RatioD. Construction Code
E. Rim Diameter
F. Service Description
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(A) P-Metric Tire:The United States version of a
metric tire sizing system. The letter ªPº 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 ª70,º as shown in item ªCº of
the illustration, it would mean that the tire's sidewall is
70% 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:These characters represent
the load range and the speed rating of a tire. The
load range represents the load carrying 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 ªAº to ªZº.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.
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)
before a tire has built up heat from driving. See
In¯ation - Tire Pressure on page 5-57.
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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 4-32.
GAWR FRT:Gross Axle Weight Rating for the front
axle, see
Loading Your Vehicle on page 4-32.
GAWR RR:Gross Axle Weight Rating for the rear axle,
see
Loading Your Vehicle on page 4-32.
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.
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). SeeLoading Your Vehicle on page 4-32.
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.
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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 5-57andLoading Your Vehicle on page 4-32.
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 5-62.
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 5-64.
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 4-32.
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 4-32.
5-55

Run-Flat Tires
Your vehicle, when new, had run-¯at tires. There's no
spare tire, no tire changing equipment and no place
to store a tire in the vehicle. Run-¯at tires perform so
well without any air that a Tire Pressure Monitor
(TPM) is used to alert you if a tire has lost pressure.
If a tire goes ¯at, you won't need to stop on the side of
the road to change the tire. You can just keep on
driving. The shorter the distance you drive and the
slower the speed, the greater the chance that the tire will
not have to be replaced. If you drive on a de¯ated
run- ¯at tire for 50 miles (80 km) or less and at speeds
of 55 mph (90 km/h) or less, there is a good chance
that the tire can be repaired. The tire can operate
effectively with no air pressure for up to 200 miles
(320 km) at speeds up to 55 mph (90 km/h), but the tire
would then have to be replaced. When a tire is ®lled
with air, it provides a cushion between the road and the
wheel. Because you won't have this cushion when
driving on a de¯ated 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've driven
on the tire in a de¯ated condition. When a tire has been
damaged, or if you've driven any distance on a
run-¯at tire, check with an authorized run-¯at tire service
center 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. As soon as possible, contact the nearest
authorized GM or run-¯at servicing facility for inspection
and repair or replacement. To locate the nearest GM
or run-¯at servicing facility, call Roadside Assistance.
For phone numbers and Roadside Service details
see
Roadside Service on page 7-5.
{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.
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The valve stems on your run-¯at tires have sensors that
are part of the Tire Pressure Monitor System (TPMS).
See
Tire Pressure Monitor System on page 5-58. These
sensors contain batteries which are designed to last
for 10 years under normal driving conditions. See your
dealer if you ever need to have a wheel replaced,
or if the sensors ever need replacement.
Notice:Using liquid sealants can damage the tire
valves and tire pressure monitor sensors in your
run-¯at tires. This damage would not be covered
by warranty. Don't use liquid sealants in your
run-¯at tires.
In¯ation - Tire Pressure
The 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 4-32for more information on the Tire and Loading
Information label.
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
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When to Check
Check your tires once a month or more.
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. Check
tire in¯ation pressure when the tire is 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. 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 Pressure Monitor (TPM)
Your vehicle has a Tire Pressure Monitor (TPM) that
sends tire pressure information to the Driver Information
Center (DIC). Using the DIC control buttons, the
driver is able to check tire pressure levels in all four
road tires. See
Tire Pressure Monitor System on
page 5-58andDIC Controls and Displays on page 3-55for additional information.
Tire Pressure Monitor System
The Tire Pressure Monitor (TPM) System on your
vehicle, uses radio and sensor technology to check tire
pressure levels. Sensors, mounted on each tire and
wheel assembly transmit tire pressure readings to
a receiver located in the vehicle. The TPM sensors
transmit tire pressure readings once every 60 seconds
while the vehicle is being driven and once every
60 minutes when the vehicle is stationary for more than
15 minutes. Using the Driver Information Center
(DIC), tire pressure levels can be viewed by the driver.
The TPM system also uses the DIC to warn the
driver when air pressure, in one or more tires, falls
below 25 psi (172 kPa) or is above 38 psi (262 kPa).
For additional information and details about the
DIC operation and displays see
DIC Controls and
Displays on page 3-55andDIC Warnings and Messages
on page 3-57.
5-58