2006 CADILLAC STS Owners Manual

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 5-66.
Make certain that all wheel nuts are properly tightened.
See “Wheel Nut Torque” underCapacities and
Specications on page 5-116.
{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
(STS Only) on page 5-83.
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.
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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 molded onto 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 5-58for
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.
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.
5-72

{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 (STS Only) on page 5-94.
{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.
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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 5-66.
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). See
Loading Your Vehicle on page 4-32, 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 5-76.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 5-72andAccessories
and Modications on page 5-3for additional information.
5-74

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.
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.
5-75

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.
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 may need to
be checked. If you notice your vehicle vibrating when
driving on a smooth road, your tires and wheels
may need to be rebalanced. See your dealer 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 if any of these conditions exist.
Your dealer 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.
5-76

If you need to replace any of your wheels, wheel bolts,
or wheel nuts, replace them only with new GM
original equipment parts. This way, you will be sure to
have the right wheel, wheel bolts, and wheel nuts
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 (STS Only) on page 5-83for
more information.
Used Replacement Wheels
{CAUTION:
Putting a used wheel on your 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.
5-77

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. 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.
5-78