Saab 2007 Flat spotting, When It Is Time for New Tires, Treadwear indicators, Wear indicators

224 Car care and technical information

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.

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.

SG840

Wear indicators

Treadwear indicators

The tires incorporate wear indicators in the form of smooth, treadless strips across the width, which become visible when only 2/32" (1.6 mm) of tread remains. As soon as the indicators become visible, new tires should be fitted without delay.

Make sure you are familiar with the legal limit for minimum tread depth in your country and also any regulations gov- erning the use of winter (snow) tires.