Saab 2007 9-3 - Manual (Page 243)

243 Car care
certain that all wheel nuts are properly tight-
ened. See page 258. Flat spotting
All 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 bal-
ancing.
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. If
the outdoor temperature is low it takes a
longer distance.
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.
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 tire” on
page 257.
93_U S_M 07.book Page 243 W ednesday, A pril 12, 2006 9:30 A M