2005 CADILLAC STS tire size

Any time you notice unusual wear, rotate your tires as
soon as possible and check wheel alignment. Also
check for damaged tires or wheels. SeeWhen It Is Time
for New Tires on page 5-67andWheel Replacement
on page 5-71for more information.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The rst rotation
is the most important. SeeScheduled Maintenance
on page 6-4.
When rotating P235/50R17 or 255/45ZR18 size tires,
always use the correct rotation pattern shown here.Do not include the compact spare tire in your tire
rotation.
After the tires have been rotated, adjust the front and
rear ination pressures as shown on the Tire and
Loading Information label.
Vehicles equipped with the Tire Pressure Monitor (TPM)
system will need to have the sensors reset after a tire
rotation, seeTire Pressure Monitor System on
page 5-62.
Make certain that all wheel nuts are properly tightened.
See “Wheel Nut Torque” underCapacities and
Specications on page 5-106.
5-66

{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after a time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
places where the wheel attaches to the vehicle.
In an emergency, you can use a cloth or a
paper towel to do this; but be sure to use a
scraper or wire brush later, if needed, to get all
the rust or dirt off. SeeChanging a Flat Tire on
page 5-74.
When It Is Time for New Tires
One way to tell when it’s
time for new tires is to
check the treadwear
indicators, which will
appear when your tires
have only 1/16 inch
(1.6 mm) or less of tread
remaining.
You need a new tire if any of the following statements
are true:
You can see the indicators at three or more places
around the tire.
You can see cord or fabric showing through the
tire’s rubber.
The tread or sidewall is cracked, cut or snagged
deep enough to show cord or fabric.
The tire has a bump, bulge or split.
The tire has a puncture, cut or other damage that
can’t be repaired well because of the size or
location of the damage.
5-67

Buying New Tires
To nd out what kind and size of tires you need, look at
the Tire and Loading Information label. SeeLoading
Your Vehicle on page 4-30, for an example of the label
and where it can be found on your vehicle.
The tires installed on your vehicle when it was new had a
Tire Performance Criteria Specication (TPC Spec)
number on each tire’s sidewall. When you get new tires,
GM recommends that you get tires with that same TPC
Spec number. That way your vehicle will continue to have
tires that are designed to give proper endurance,
handling, speed rating, load range, traction, ride, tire
pressure monitoring system performance and other
things during normal service on your vehicle. If your tires
have an all-season tread design, the TPC number will be
followed by an “MS” (for mud and snow).
The optional 18-inch performance tires, size 255/
45ZR18 99Y, used on some vehicles, meet the General
Motors Tire Performance Criteria Specication (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.
If you replace your tires with those not having a TPC
Spec number, make sure they are the same size,
load range, speed rating and construction type (bias,
bias-belted or radial) as your original tires.
Winter tires with the same speed rating as your original
equipment tires may not be available for H, V, W
and ZR speed rated tires. If you choose snow tires with
a lower speed rating, never exceed the tire’s maximum
speed capability.
If you replace your vehicle’s tires with those not having
a TPC Spec number, the tire pressure monitoring
system may give an inaccurate low-pressure warning.
Non-TPC Spec tires may give a low-pressure warning
that is higher or lower than the proper warning level you
would get with TPC Spec numbered tires.
5-68

{CAUTION:
Mixing tires could cause you to lose control
while driving. If you mix tires of different sizes
(other than those originally installed on your
vehicle) or types (radial and bias-belted tires),
the vehicle may not handle properly, and you
could have a crash. Using tires of different
sizes (other than those originally installed on
your vehicle) may also cause damage to your
vehicle. Be sure to use the correct size and
type tires on all wheels. It is all right to drive
with your compact spare temporarily, it was
developed for use on your vehicle. See
Compact Spare Tire on page 5-84.
{CAUTION:
If you use bias-ply tires on your vehicle, the
wheel rim anges could develop cracks after
many miles of driving. A tire and/or wheel
could fail suddenly, causing a crash. Use only
radial-ply tires with the wheels on your vehicle.
Vehicles equipped with performance tires P235/
50R17 95V (front axle) and P255/45R17 98V (rear axle)
are mounted on wheels with different rim widths. The
front axle tires are mounted on rims 7.5 inches (19.05 cm)
wide and the rear axle tires require wheels with a
minimum rim width of 8 inches (20.32 cm). The original
equipment wheels designed for P255/45R17 98V size
tires are etched with the words REAR ONLY. When
replacing P255/45R17 98V size tires have them mounted
on wheels with a minimum width of 8 inches (20.32 cm)
and marked REAR ONLY. SeeWheel Replacement on
page 5-71.
5-69

Tire Chains
{CAUTION:
If your vehicle has P255/45R17 98V,
P255/45R18 99W or 255/45ZR18 99Y size tires,
do not use tire chains, there is not enough
clearance.
Tire chains used on a vehicle without the
proper amount of clearance can cause damage
to the brakes, suspension or other vehicle
parts. The area damaged by the tire chains
could cause you to lose control of your vehicle
and you or others may be injured in a crash.
CAUTION: (Continued)
CAUTION: (Continued)
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
conditions. Follow that manufacturer’s
instructions. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it is contacting your vehicle, and do
not spin your wheels.
If you do nd traction devices that will t,
install them on the rear tires only.
Notice:If your vehicle has P235/50R17 95S size
tires, use tire chains only where legal and only when
you must. Use only SAE Class “S” type chains
that are the proper size for your tires. Install them
on the rear tires and tighten them as tightly as
possible with the ends securely fastened. Drive
slowly and follow the chain manufacturer’s
instructions. If you can hear the chains contacting
your vehicle, stop and retighten them. If the contact
continues, slow down until it stops. Driving too
fast or spinning the wheels with chains on will
damage your vehicle.
5-73

14. Tighten the wheel nuts
rmly in a crisscross
sequence as shown.
Notice:Improperly tightened wheel nuts can lead
to brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper
torque specication. SeeCapacities and
Specifications on page 5-106for the wheel nut
torque specication.
Notice:Wheel covers will not t on your compact
spare. If you try to put a wheel cover on the compact
spare, you could damage the cover or the spare.
Do not try to put a wheel cover on your compact spare
tire. It will not t. Store the wheel cover in the trunk
until you have the at tire repaired or replaced.Storing a Flat or Spare Tire and
Tools
{CAUTION:
Storing a jack, a tire, or other equipment in the
passenger compartment of the vehicle could
cause injury. In a sudden stop or collision,
loose equipment could strike someone. Store
all these in the proper place.
After you have put the compact spare tire on your
vehicle, you will need to do the following to store the at
tire in your trunk.
1. Store the jack and wheel wrench in their
compartment in the trunk.
When storing the jack, in the container, it must be
raised until the screw end is ush with the edge
of the jack.
2. Store the at tire as far forward in the trunk as
possible.
The compact spare is for temporary use only. Replace
the compact spare tire with a full-size tire as soon
as you can.
5-83

Use the following diagram as a guide for storing the
compact spare tire in the trunk:
A. Compact Spare
Tire Cover
B. Plastic Wing Nut
C. Retainer
D. Jack Container
with Wheel Wrench
and JackE. Compact
Spare Tire
F. Foam Insert
G. Bolt
H. Wheel Wrench
I. Jack
J. Jack ContainerCompact Spare Tire
Although the compact spare tire was fully inated when
your vehicle was new, it can lose air after a time. Check
the ination pressure regularly. It should be
60 psi (420 kPa).
After installing the compact spare on your vehicle, you
should stop as soon as possible and make sure
your spare tire is correctly inated. The compact spare
is made to perform well at speeds up to 65 mph
(105 km/h) for distances up to 3,000 miles (5 000 km),
so you can nish your trip and have your full-size
tire repaired or replaced where you want. Of course, it
is best to replace your spare with a full-size tire as soon
as you can. Your spare will last longer and be in
good shape in case you need it again.
Notice:When the compact spare is installed, do
not take your vehicle through an automatic car wash
with guide rails. The compact spare can get
caught on the rails. That can damage the tire and
wheel, and maybe other parts of your vehicle.
Do not use your compact spare on other vehicles.
And do not mix your compact spare tire or wheel with
other wheels or tires. They will not t. Keep your
spare tire and its wheel together.
Notice:Tire chains will not t your compact spare.
Using them can damage your vehicle and can
damage the chains too. Do not use tire chains on
your compact spare.
5-84

Owner Checks and Services
These owner checks and services should be performed
at the intervals specied to help ensure the safety,
dependability and emission control performance of your
vehicle. Your GM Goodwrench
®dealer can assist
you with these checks and services.
Be sure any necessary repairs are completed at once.
Whenever any uids or lubricants are added to your
vehicle, make sure they are the proper ones, as shown
inRecommended Fluids and Lubricants on page 6-12.
At Each Fuel Fill
It is important to perform these underhood checks at
each fuel ll.
Engine Oil Level Check
Check the engine oil level and add the proper oil if
necessary. SeeEngine Oil on page 5-15for further
details.
Notice:It is important to check your oil regularly
and keep it at the proper level. Failure to keep your
engine oil at the proper level can cause damage
to your engine not covered by your warranty.
Engine Coolant Level Check
Check the engine coolant level and add
DEX-COOL®coolant mixture if necessary. SeeEngine
Coolant on page 5-22for further details.
Windshield Washer Fluid Level Check
Check the windshield washer uid level in the windshield
washer tank and add the proper uid if necessary.
At Least Once a Month
Tire Ination Check
Visually inspect your vehicle’s tires and make sure they
are inated to the correct pressures. Do not forget to
check the spare tire. SeeTires on page 5-53for further
details. Check to make sure the spare tire is stored
securely. SeeChanging a Flat Tire on page 5-74.
Tire Wear Inspection
Tire rotation is recommended if your vehicle has the
same size tires at all four wheel positions and may
be required for high mileage highway drivers prior to
the Engine Oil Life System service notication. Check
the tires for wear and, if necessary, rotate the tires.
SeeTire Inspection and Rotation on page 5-65.
6-9