„Shampoo for tyres“

Spring is here and it’s time to put on those summer tyres. Eugen Geyer, customer service engineer for tyres at Continental reveals the best tips and tricks for safe summer driving.

Mr Geyer - spring is here and it’s time for us to take off our winter tyres. Do you have any advice to offer?

 The most important thing to remember is that, for tyres, spring does not necessarily start on the date indicated in your calendar. As a rule of thumb, winter tyres should be used from October to Easter or mid-April.

During this time, average temperatures in Germany are statistically lower than 7 degrees Celsius. The average temperature only rises sufficiently to warrant the use of summer tyres around Easter. This is when the benefits of summer tyres become apparent with better handling, shorter braking distances and lower fuel consumption than winter tyres.

So what do you do if you’ve fitted your summer tyres and then snow showers and hailstones come along in the middle of April?

This does happen – sometimes there’s even the odd hailstorm in summer. When you change your tyres, you should be clear in your mind that you are no longer driving on winter tyres and therefore you need to be very careful when driving in severe weather conditions. Ideally, you should head to the nearest lay-by and wait until the roads clear up.

Many motorists store and change their own tyres. What advice do you have for them?

It’s important to keep tyres in a suitable storage area. Tires should be stored in a cool, dry place away from any oil or chemicals. For example, lofts are not suitable as they heat up slightly during the summer and the heat will damage winter tire rubber. Your storage space should be cool, dry and protected from direct sunlight. When you come to change your tires, you should perform a basic check to determine whether there are there any foreign bodies in the tread or slits in the rubber. You should also clean the rims to ensure that there is no dirt between the rim centres and the wheel hubs, which can reduce driving comfort.

You mentioned that tyres should not be brought into contact with oil. However, this can easily occur if you roll the tyres through the garage towards your car.

Natural rubber is a material which, when subjected to high temperatures and chemical supplements during the manufacturing process, is transformed into synthetic rubber. Tires are mainly composed of synthetic rubber which reacts to oil and chemical fumes, and this may harden or soften the rubber. However, if a tyre comes briefly into contact with oil, this should not be a problem. You should wash your tyre immediately, ideally with water and perhaps a bit of shampoo. Then rinse the tyre thoroughly.

What is the best way to store winter tyres?

Ideally, wheel assemblies with rims should be hung on the wall or on a tyre rim holder. If you leave them standing, you should rotate them slightly every few weeks to ensure that their weight is not resting on the same area of rubber for the whole summer. This generally proves too laborious in practice so I would be more inclined to recommend that people hang up their tyres. You can also stack wheel assemblies horizontally as they keep their shape on the rims. When removing wheels, you should mark their fitted position on the rubber or rims using a piece of chalk or similar implement – FL for front left and BR for back right.

Is it possible to fit tyres in different positions this summer and switch tyres from the rear to the front axle?

Yes, this is possible. For example, tyres on the drive axle always wear down a bit quicker than those on the non-driven axis. Therefore a tyre change is a great opportunity to balance your tyres and switch the back tyres to the front and vice versa. If you do this, you should then allow the tyres on the front axle to regain their balance to ensure optimal driving comfort.

Is it possible to change tyres diagonally – that is from left to right and vice versa?

It’s possible but we’d advise against it. It changes the rotating direction of the tyre which can significantly reduce driving comfort in the first two to three thousand kilometres. Indeed, when used on one side, a tyre develops a certain wear pattern a bit like an eraser. This is quite normal. However, if you then turn it around and change it from the left to the right-hand side of the car, it will not run very well. This has absolutely no impact in terms of safety but makes your car less comfortable to drive. Other more specific recommendations can be found in your manufacturer’s handbook and these should also be observed.

Many motorists store their tyres in a workshop or at a tyre dealership rather than at home. Often when you’re due a tyre change, you’re told that you should consider buying new tyres. As a layman, how can I tell whether the tyres are actually unserviceable or whether they’re just trying to sell me something?

There are two factors which should be considered when replacing tyres. The first of these is the wear limit. The law states that if you have 1.6 millimetres of remaining tread, you have reached the wear limit and should buy new tyres. If you continue to use these tyres, you risk losing your insurance cover and gaining points on your licence. We recommend buying new summer tyres when your tread is less than three millimetres deep as braking distances on wet roads will already be significantly increased. This is not just marketing waffle – safety is seriously compromised when the tread has been excessively worn down. The second reason for changing your tyres is age. In the recommendations, it is clearly stated that tyres should be no more than ten years old as the rubber ages and the tyres do not handle the road as well. The age of a tyre is indicated by the four-digit number on the tire wall - the first pair of digits represents the calendar production week and the second pair indicates the year of production. For example, 1208 means the twelfth calendar week of 2008.

Tyre pressure is also important. Studies have shown that a third of all motorists almost never check their tyre pressure.

This is no doubt because people trust their tyres and consider them to be reliable, premium products. However, tyre pressure should be checked every two to four weeks if you do not have an on-board tyre pressure control system. Foreign bodies in tyres can cause a gradual loss of air. If you do not notice this, you may endanger yourself when travelling at high speeds or taking bends. Furthermore, your tyres will wear down faster, thus significantly increasing fuel consumption and reducing the tyres’ lifespan. If your tyres are underinflated by 0.4 bar their lifespan may be reduced by up to 30 percent.

We are always told that tyre pressure should be checked when the tyres are cold. However, what happens if the nearest garage is a few miles away?

 This is not a problem. Tires only heat up enough to affect air pressure on longer journeys at high speeds. If you have driven for two hours at 160 km/h on the motorway, you should not check your tyre pressure straight away as it will be a few tenths of a bar over the recommended level. Under no circumstances should you then let air out of your tyres. As soon as the tyres cool down, the pressure will be too low. However, if you have only driven a few kilometers at 60 or 80 km/h through the city or on country roads, your tyres will be relatively cool so you can safely check the air pressure and make adjustments based on manufacturer recommendations where necessary.