218 Car care and technical informationWhen to checkCheck your tires once a month or more.
Don’t forget your compact spare tire. It
should be at 60 psi (420 kPa).How to CheckUse a good quality pocket-type gauge to
check tire pressure. You can’t tell if your
tires are properly inflated simply by looking
at them. Radial tires may look properly infla-
ted even when they’re underinflated.
Be sure to put the valve caps back on the
valve stems. They help prevent leaks by
keeping out dirt and moisture.Tire Inspection and RotationAny time you notice unusual wear, rotate
your tires as soon as possible and check
wheel alignment. Also check for damaged
tires or wheels. See “When It Is Time for
New Tires” on page 219 and “Wheel Repla-
cement” on page 222 for more information.
The purpose of regular rotation is to achieve
more uniform wear for all tires on the
vehicle. The first rotation is the most impor-
tant.
When rotating your tires, always use the
correct rotation pattern. Left front tire to left
rear. Left rear tire to right front. Right front to
right rear. Right rear to left front.
Don’t include the compact spare tire in your
tire rotation.
After the tires have been rotated, adjust the
front and rear inflation pressures as shown
on the Tire-Loading Information label. Make certain that all wheel nuts are properly tigh-
tened. See page 233.
Flat spottingAll tires get hot, especially on long journeys
or when the car is driven hard. After the car
has been parked with hot tires and the tires
have cooled down, a flat spot can form in the
tire, where it is in contact with the ground.
The same can occur if the car has not been
moved for a long time.
Flat spots can cause vibration that can be
felt through the steering wheel, similar to
that experienced when the wheels need
balancing.
Flat spots of this type disappear once the
tires get hot again, usually after 10–15 miles
(20–25 km) of driving at cruising speed.
WARNING
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 you need to, to get all the
rust or dirt off. See “Changing a wheel” on
page 231.
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222 Car care and technical informationWheel Alignment and Tire BalanceThe wheels on your vehicle were aligned
and balanced carefully at the factory to give
you the longest tire life and best overall per-
formance.
Scheduled wheel alignment and wheel
balancing are not needed. However, if you
notice unusual tire wear or your vehicle pul-
ling one way or the other, the alignment may
need to be reset. If you notice your vehicle
vibrating when driving on a smooth road,
your wheels may need to be rebalanced.Wheel ReplacementReplace 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.
If you need to replace any of your wheels,
wheel bolts or wheel nuts, replace them only
with new Saab original equipment parts.
This way, you will be sure to have the right
wheel, wheel bolts and wheel nuts for your
vehicle.Make sure tires with Tire Pressure Monitors
are fitted as replacement tires on cars with
this system.
Notice:
The wrong wheel can also cause
problems with bearing life, brake coo-
ling, speedometer or odometer calibra-
tion, headlamp aim, bumper height,
vehicle ground clearance and tire or tire
chain clearance to the body and chassis.
See “Changing a wheel” on page 231.
Used Replacement Wheels
WARNING
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.
WARNING
When fitting just
one
new pair of tires,
these should be fitted to the rear wheels,
as these are more critical to the direc-
tional stability of the car (e.g. on braking
or in a skid). The existing rear wheels
should therefore be moved to the front.
WARNING
Putting a used wheel on your vehicle is
dangerous. You can’t know how it’s been
used or how far it’s been driven. It could
fail suddenly and cause a crash. If you
have to replace a wheel, use a new GM
original equipment wheel.
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