2008 CADILLAC CTS tire size

Tire and Loading Information Label
A vehicle specic Tire and Loading Information
label is attached to the vehicle’s center pillar
(B-pillar). With the driver’s door open, you will nd
the label attached below the door lock post (striker).The Tire and Loading Information label shows the
number of occupant seating positions (A), and the
maximum vehicle capacity weight (B) in kilograms
and pounds.
The Tire and Loading Information label also shows
the tire size of the original equipment tires (C) and
the recommended cold tire ination pressures (D).
For more information on tires and ination seeTires
on page 5-58andInflation - Tire Pressure on
page 5-66.
There is also important loading information on the
Certication label. It tells you the Gross Vehicle
Weight Rating (GVWR) and the Gross Axle Weight
Rating (GAWR) for the front and rear axle; see
“Certication Label” later in this section.
Example Label
4-23

Tires..............................................................5-58
Winter Tires.................................................5-60
Tire Sidewall Labeling...................................5-60
Tire Terminology and Denitions.....................5-63
Ination - Tire Pressure.................................5-66
High-Speed Operation...................................5-68
Tire Pressure Monitor System.........................5-69
Tire Pressure Monitor Operation.....................5-70
Tire Inspection and Rotation...........................5-74
When It Is Time for New Tires.......................5-75
Buying New Tires.........................................5-76
Different Size Tires and Wheels......................5-78
Uniform Tire Quality Grading..........................5-78
Wheel Alignment and Tire Balance..................5-80
Wheel Replacement......................................5-80
Tire Chains..................................................5-82
If a Tire Goes Flat........................................5-82
Tire Sealant and Compressor Kit
(With Sealant Selector Switch)....................5-84
Tire Sealant and Compressor Kit
(Without Sealant Selector Switch)................5-93
Changing a Flat Tire...................................5-102
Removing the Spare Tire and Tools..............5-104
Removing the Flat Tire and Installing the
Spare Tire..............................................5-105Storing a Flat or Spare Tire and Tools...........5-110
Compact Spare Tire....................................5-111
Appearance Care..........................................5-112
Interior Cleaning.........................................5-112
Fabric/Carpet..............................................5-113
Leather......................................................5-114
Instrument Panel, Vinyl, and Other Plastic
Surfaces.................................................5-115
Wood Panels..............................................5-115
Speaker Covers..........................................5-115
Care of Safety Belts....................................5-115
Weatherstrips
.............................................5-115
Washing Your Vehicle..................................5-116
Cleaning Exterior Lamps/Lenses....................5-116
Finish Care................................................5-116
Windshield and Wiper Blades.......................5-117
Aluminum or Chrome-Plated Wheels
and Trim................................................5-118
Tires.........................................................5-118
Sheet Metal Damage...................................5-119
Finish Damage...........................................5-119
Underbody Maintenance...............................5-119
Chemical Paint Spotting...............................5-119
Vehicle Care/Appearance Materials................5-120
Section 5 Service and Appearance Care
5-2

CAUTION: (Continued)

Underinated tires pose the same
danger as overloaded tires. The
resulting accident could cause serious
injury. Check all tires frequently to
maintain the recommended pressure.
Tire pressure should be checked when
your tires are cold. SeeInflation - Tire
Pressure on page 5-66.
Overinated 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, old tires can cause accidents. If
your tread is badly worn, or if your tires
have been damaged, replace them.
SeeHigh-Speed Operation on page 5-68for
ination pressure adjustment for high
speed driving.
Low-Prole Performance Tires
If your vehicle has 235/50ZR18 or P235/50R18
size tires, they are classied as low-prole 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 ination pressure
and, when possible avoid contact with curbs,
potholes, and other road hazards.
Summer Performance Tires
Many General Motors high performance models
come factory-equipped with tires that are optimized
for maximum dry and wet road performance while
still retaining satisfactory tread life, excellent
durability, and low noise levels. In severe winter
climates where snowfall may be signicant, these
tires may be found to provide less traction.
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Winter Tires
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 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, seeBuying
New Tires on page 5-76.
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 the original equipment
tires.
Winter tires with the same speed rating as your 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.
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.Passenger (P-Metric) Tire Example
5-60

(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 5-78.(G) Maximum Cold Ination Load Limit
:Maximum load that can be carried and the
maximum pressure needed to support that load.
(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).Compact Spare Tire Example
5-61

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 5-111andIf a Tire Goes Flat
on page 5-82.
(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 seeInflation - Tire Pressure on
page 5-66.(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.
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(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 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,
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.
5-63

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
the Vehicle on page 4-22.
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 economyIf your tires have too much air (over-ination),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazards
A vehicle specic Tire and Loading Information
label is attached to your vehicle. 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, seeLoading
the Vehicle on page 4-22. How you load your
vehicle affects vehicle handling and ride comfort.
Never load your vehicle with more weight than it
was designed to carry.
5-66