The service life of tyres is dependent on tyre pressure, driving style and fitting.

Fig. 151 Tyre tread wear indicators

Fig. 151 Tyre tread wear indicators

Wear indicators
The original tyres on your vehicle have 1.6 mm high “tread wear indicators”  fig. 151 running across the tread. Depending on the make, there will be six to eight of them evenly spaced around the tyre. Markings on the tyre sidewall (for instance the letters “TWI” or other symbols) indicate the positions of the tread wear indicators. The minimum tread depth required by law is 1.6 mm (measured in the tread grooves next to the tread wear indicators). Worn tyres must be replaced. Different figures may apply in export countries .

Tyre pressure
Incorrect tyre pressure causes premature wear and could cause tyre blow-out.

For this reason, the tyre pressure should be checked at least once per month.

Driving style
Fast cornering, heavy acceleration and hard braking all increase tyre wear.

Changing wheels around If the front tyres are worn considerably more than the rear ones it is advisable to change them around as shown  fig. 152. All the tyres will then last for about the same time.

Wheel balance
The wheels on new vehicles are balanced. However, various factors encountered in normal driving can cause them to become unbalanced, which results in steering vibration.

Unbalanced wheels should be rebalanced, as they otherwise cause excessive wear on steering, suspension and tyres. A wheel must also be rebalanced when a new tyre is fitted.

Incorrect wheel alignment
Incorrect wheel alignment causes excessive tyre wear, impairing the safety of the vehicle. If tyres show excessive wear, you should have the wheel alignment checked by an Authorised Service Centre.

WARNING

There is a serious danger of accidents if a tyre bursts during driving! • The tyres must be replaced at the latest when the tread is worn down to the tread wear indicators. Failure to do so could result in an accident. Worn tyres do not grip well at high speeds on wet roads. There is also a greater risk of “aquaplaning”.
• At continuously high speeds, a tyre with insufficient pressure flexes more. This causes it to overheat. This can cause tread separation and tyre blow-out. Risk of accident. Always observe the recommended tyre pressures.
• If tyres show excessive wear, you should have the running gear checked by an Authorised Service Centre.
• Keep chemicals such as oil, fuel and brake fluid away from tyres.
• Damaged wheels and tyres must be replaced immediately!

For the sake of the environment
Under-inflated tyres will increase fuel consumption.