2009 CADILLAC STS Owners Manual

{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. SeeCompact Spare Tire on
page 5-114.
{CAUTION:
If you use bias-ply tires on the 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 the
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 could 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 5-66.
5-75

Your vehicle’s original equipment tires are
listed on the Tire and Loading Information label.
SeeLoading the Vehicle on page 4-24, for
more information about the Tire and Loading
Information label and its location on your vehicle.
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, antilock 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 5-74andAccessories
and Modifications on page 5-3for additional information.
5-76

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.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specied
government test course. For example, a tire
graded 150 would wear one and a half (1.5) 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 signicantly from the
norm due to variations in driving habits, service
practices, and differences in road characteristics
and climate.
5-77

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 specied government test
surfaces of asphalt and concrete. A tire marked C
may have poor traction performance.
{WARNING:
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration,
cornering, hydroplaning, or peak traction
characteristics.
Temperature – A, B, C
The temperature grades are A (the highest), B,
and C, representing the tire’s resistance to the
generation of heat and its ability to dissipate heat
when tested under controlled conditions on a
specied indoor laboratory test wheel. Sustained
high temperature can cause the material of the tire
to degenerate and reduce tire life, and excessive
temperature can lead to sudden tire failure. The
grade C corresponds to a level of performance
which all passenger car tires must meet under the
Federal Motor Vehicle Safety Standard No. 109.
Grades B and A represent higher levels of
performance on the laboratory test wheel than
the minimum required by law.
{WARNING:
The temperature grade for this tire is
established for a tire that is properly inated
and not overloaded. Excessive speed,
underination, or excessive loading, either
separately or in combination, can cause
heat buildup and possible tire failure.
5-78

Wheel Alignment and Tire Balance
The tires and wheels on your vehicle were aligned and
balanced carefully at the factory to give you the longest
tire life and best overall performance. Adjustments to
wheel alignment and tire balancing will not be necessary
on a regular basis. However, if you notice unusual tire
wear or your vehicle pulling to one side or the other, the
alignment might need to be checked. If you notice your
vehicle vibrating when driving on a smooth road, the tires
and wheels might need to be rebalanced. See your
dealer/retailer for proper diagnosis.
Wheel Replacement
Replace any wheel that is bent, cracked, or badly rusted
or corroded. If wheel nuts keep coming loose, the wheel,
wheel bolts, and wheel nuts should be replaced. If the
wheel leaks air, replace it (except some aluminum
wheels, which can sometimes be repaired). See your
dealer/retailer if any of these conditions exist.
Your dealer/retailer will know the kind of wheel
you need.
Each new wheel should have the same load-carrying
capacity, diameter, width, offset, and be mounted
the same way as the one it replaces.
5-79

If you need to replace any of your wheels, wheel bolts,
wheel nuts, or Tire Pressure Monitor System (TPMS)
sensors, replace them only with new GM original
equipment parts. This way, you will be sure to have
the right wheel, wheel bolts, wheel nuts, and TPMS
sensors for your vehicle.
{CAUTION:
Using the wrong replacement wheels, wheel bolts,
or wheel nuts on your vehicle can be dangerous.
It could affect the braking and handling of your
vehicle, make your tires lose air and make you
lose control. You could have a collision in which
you or others could be injured. Always use the
correct wheel, wheel bolts, and wheel nuts for
replacement.Notice:The wrong wheel can also cause problems
with bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper height,
vehicle ground clearance, and tire or tire chain
clearance to the body and chassis.
SeeChanging a Flat Tire on page 5-104for more
information.
Used Replacement Wheels
{CAUTION:
Putting a used wheel on the vehicle is dangerous.
You cannot know how it has been used or how
far it has been driven. It could fail suddenly and
cause a crash. If you have to replace a wheel,
use a new GM original equipment wheel.
5-80

Tire Chains
{CAUTION:
If your VEHICLE has P255/45R17, P255/45ZR18,
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 the 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
CAUTION: (Continued)
CAUTION: (Continued)
conditions. Follow that manufacturer’s instructions.
To help avoid damage to the vehicle, drive slowly,
readjust, or remove the device if it is contacting
the vehicle, and do not spin the 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 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.
5-81

Lifting the Vehicle (STS-V)
{CAUTION:
Lifting a vehicle can cause an injury. The vehicle
can slip off the jack and roll over you or other
people. You and they could be badly injured.
Find a level place to lift your vehicle. To help
prevent the vehicle from moving:
1. Hold the brake pedal down with your right foot.
2. Move the shift lever in PARK (P) by pressing
the button on the front of the shift lever while
pushing the lever all the way toward the front
of the vehicle. Release the button.
3. With your right foot still holding the brake
pedal down, set the parking brake with your
left foot.
4. Turn off the engine.
To be even more certain the vehicle will not move,
you can put blocks in front of and behind the wheels.
Also, seeShifting Into Park on page 2-34and
Parking Brake on page 2-33for additional
information.
{CAUTION:
Getting under a vehicle when it is jacked up is
dangerous. If the vehicle slips off the jack, you
could be badly injured or killed. Never get under
a vehicle when it is supported only by a jack.
{CAUTION:
Raising the vehicle with the jack improperly
positioned can damage the vehicle or the vehicle
may fall and cause your or others injury.
If you ever use a jack to lift your vehicle, follow the
instructions that came with the jack, and be sure to
use the correct lifting points to avoid damaging
your vehicle.
5-82