tire size CADILLAC STS 2007 1.G User Guide

When rotating P235/50R17 size tires or
255/45ZR18 size tires, always use the correct
rotation pattern shown here.
If your vehicle has a compact spare tire, do not
include the compact spare tire in the 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 that have the Tire Pressure Monitor
System (TPMS) will need to have the TPMS
sensors reset after a tire rotation, seeTire
Pressure Monitor System on page 433.Make certain that all wheel nuts are properly
tightened. See “Wheel Nut Torque” under
Capacities and Specications on page 498.
{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after 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 464.
439

When It Is Time for New Tires
One way to tell when it
is 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 cannot be repaired well because of the
size or location of the damage.
440

Buying New Tires
GM has developed and matched specic tires for
your vehicle. The original equipment tires
installed on your vehicle, when it was new, were
designed to meet General Motors Tire
Performance Criteria Specication (TPC Spec)
system rating. If you 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 specications 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 moldedonto the tire’s sidewall by the tire manufacturer. 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 423for additional information.
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.
441

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
snow tires with a lower speed rating, never exceed
the tire’s maximum speed capability.
{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), brands, 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), brands, or
types may also cause damage to your
vehicle. Be sure to use the correct size,
brand, and type of tires on all wheels. It is
all right to drive with your vehicle’s
compact spare temporarily, it was
developed for use on your vehicle. See
Compact Spare Tire on page 475.
{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.
If you must replace your vehicle’s tires with those
that do not have a TPC Spec number, make
sure they are the same size, load range, speed
rating, and construction type (radial and
bias-belted tires) as your vehicle’s original tires.
Vehicles that have a tire pressure monitoring
system may give an inaccurate low-pressure
warning if non-TPC Spec rated tires are installed
on it. Non-TPC Spec rated tires may give a
low-pressure warning that is higher or lower than
the proper warning level you would get with
TPC Spec rated tires. SeeTire Pressure Monitor
System on page 433.
442

Your vehicle’s original equipment tires are listed
on the Tire and Loading Information label.
This label is attached to the vehicle’s center pillar
(B-pillar). SeeLoading Your Vehicle on page 349,
for more information about the Tire and Loading
Information label and its location on your vehicle.
Vehicles that have 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 445.
Different Size Tires and Wheels
If you add wheels or tires that are a different size
than your original equipment wheels and tires,
this may affect the way your vehicle performs,
including its braking, ride and handling
characteristics, stability, and resistance to rollover.Additionally, if your vehicle has electronic systems
such as, anti-lock brakes, traction control, and
electronic stability control, the performance
of these systems can be affected.
{CAUTION:
If you add different sized wheels, your
vehicle may not provide an acceptable
level of performance and safety if tires not
recommended for those wheels are
selected. You may increase the chance
that you will crash and suffer serious
injury. Only use GM specic wheel and
tire systems developed for your vehicle,
and have them properly installed by a GM
certied technician.
SeeBuying New Tires on page 441and
Accessories and Modications on page 363for
additional information.
443

Tire Chains
{CAUTION:
If your vehicle has P255/45R17,
P255/45R18, P275/40R19, or 255/45ZR18
size tires, do not use tire chains, as 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.
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.
CAUTION: (Continued)
CAUTION: (Continued)
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 vehicle’s 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.
447

If a Tire Goes Flat
It is unusual for a tire to blowout while you are
driving, especially if you maintain your tires
properly. SeeTires on page 421. If air goes out of
a tire, It is much more likely to leak out slowly.
But if you should ever have a blowout, here are a
few tips about what to expect and what to do:
If a front tire fails, the at tire will create a drag that
pulls the vehicle toward that side. Take your
foot off the accelerator pedal and grip the steering
wheel rmly. Steer to maintain lane position,
and then gently brake to a stop well out of the
traffic lane.
A rear blowout, particularly on a curve, acts much
like a skid and may require the same correction
you would use in a skid. In any rear blowout,
remove your foot from the accelerator pedal. Get
the vehicle under control by steering the way
you want the vehicle to go. It may be very bumpy
and noisy, but you can still steer. Gently brake
to a stop, well off the road if possible.If a tire goes at, and your vehicle has a compact
spare tire, seeChanging a Flat Tire on page 464.
This information shows you how to use your
vehicle’s tire changing equipment and how
to change a at tire safely.
{CAUTION:
Lifting a vehicle and getting under it to do
maintenance or repairs is dangerous
without the appropriate safety equipment
and training. The jack provided with your
vehicle is designed only for changing a
at tire. If it is used for anything else, you
or others could be badly injured or killed
if the vehicle slips off the jack. Use the
jack provided with your vehicle only for
changing a at tire.
If your vehicle has 255/45ZR18 size tires, there is
no spare tire, jack, or tire changing equipment.
A tire inator kit, included with your vehicle, may
be used to seal small punctures in the tread
area of the tire. SeeTire Inator Kit on page 452.
451

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.
Full-Size Tire and Tools
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. Open the trunk. SeeTrunk on page 101.
2. Store the jack and wheel wrench in the jack
container 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.
3. 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.
473

Compact Spare Tire
Although the compact spare tire was fully inated
when the 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 the vehicle,
you should stop as soon as possible and make
sure the 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 the full-size tire repaired or replaced
where you want. You must calibrate the tire
ination monitor system after installing or removing
the compact spare. SeeTire Pressure Monitor
System on page 433. The system may not
work correctly when the compact spare is installed
on the vehicle. Of course, it’s best to replace
the spare with a full-size tire as soon as you can.
The 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 the compact spare on other vehicles.
And do not mix the compact spare tire or
wheel with other wheels or tires. They will not t.
Keep the 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.
475

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 380for
further details.
Notice:It is important to check the engine oil
regularly and keep it at the proper level.
Failure to keep the engine oil at the proper
level can cause damage to the engine not
covered by your warranty.
Engine Coolant Level Check
Check the engine coolant level and add
DEX-COOL®coolant mixture if necessary. See
Engine Coolant on page 389for further details.
Intercooler Coolant Level Check
(4.4L Supercharged Engine)
Check the coolant level and add DEX-COOL®
coolant mixture if necessary. SeeEngine Coolant
on page 389for further details.
Windshield Washer Fluid Level Check
Check the windshield washer uid level in
the windshield washer uid reservoir 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. SeeInation - Tire
Pressure on page 431. Check to make sure the
spare tire is stored securely. SeeChanging a Flat
Tire on page 464.
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 438.
513