Bosch Car Service - Tire Guide

What is the difference between winter and summer tires?

Would you have known? A vehicle fitted with summer tires traveling on a snow-covered road needs 43 meters to come to a standstill from a speed of 50 km/h. With winter tires, a distance of only 35 m is required – in other words a whole 7 m less. This is because summer tires no longer provide the necessary grip at temperatures below 7°C. Thanks to the special blend of rubber used and their coarser, usually deeper tread with additional sipes, winter tires ensure better adhesion.

Get safely through the year with the right tires

Statistics show that the risk of an accident is six times greater in winter than in summer. What's more: In the case of accidents, insurance companies tend to apportion some of the blame to the drivers of vehicles not fitted with the appropriate (legally specified) tires. So before you get into your vehicle it is best to take a look at the weather conditions and switch to winter tires in good time.

How important is the correct inflation pressure?

The weight of a vehicle is not borne solely by the tires, the air in them also plays an important part. The safety risk increases with every journey if the inflation pressure is too low:

• The braking distance is unnecessarily long.
• There is an increased risk of tire damage caused by excessive heat generation.
• Fuel consumption rises on account of the greater rolling resistance.

What is the right way to clean tires?

Do you tend to use a high-pressure cleaner on your car? If so, it is important to take particular care when cleaning the tires. A concentrated jet of hot water from close range can cause considerable damage, as the pressure on impact causes the temperature of the tire material to increase and small blisters to form in the rubber, thus weakening it. Possible consequences: Sudden bursting of tires under heavy load or at high speed.

Points to watch when cleaning tires:

• Maintain a distance of at least 20 cm between the end of the gun and the tire.
• Use a wide-spread rather than a concentrated jet.
• Even in the event of stubborn dirt, never direct the jet at a single point but rather move it constantly back and forth.

When do tires need changing?

There are three important factors to bear in mind: Age, tread depth and possible damage. Not to forget the minimum tread depth of 1.6 mm required by law. Our recommendation: Replace summer tires when the tread depth is down to 3 mm and 4 mm at the latest in the case of winter tires. Tires should also be replaced if they are more than 10 years old – even if the tread depth is still adequate. The age of a tire can be seen from the four-digit DOT number stamped on it. The last two digits indicate the year of manufacture and the first two show the week of manufacture.

Our advice for correct checking:

Insert a 2-euro coin (1-euro coin for summer tires) in the groove where the tread is most shallow. If the stars on the coin are no longer visible, the tread is still OK.

What is the right way to store tires?

The same problem every winter – what to do with summer tires? One alternative is to put them into storage at a workshop. Ask us about our all-round tire service. If on the other hand you intend to store wheels or tires at home, it is important to heed the following:

• Ideally, tires should be stored in a dry, dark, cool and moderately ventilated location.
• Wheels can either be hung up, placed on rim trees or laid flat.
• Tires without rims are always stored standing up.