Munich - The time for winter tyres is here. But drivers should first check whether they need new winter tyres before starting to fit their existing models. If the tread depth is only slightly deeper than the four millimetres recommended by TÜV SÜD, a new purchase can have numerous benefits. Winter tyre technology has made enormous strides in recent years; modern tyres now achieve significantly shorter braking distances on snow and ice and have far lower levels of drive-by noise.
Major tyre manufacturers launch a new generation of winter tyres roughly every four years, each time featuring extensive improvements. This progress is most obvious in the categories of wet handling and drive-by noise. "This partly results from the introduction of tyre labels that clearly display this information for drivers to read", explains Michael Staude, Head of TÜV SÜD’s Tyres and Wheels centre. Some new winter tyres now receive a "B" rating in wet braking. Every new tyre generation has succeeded in shortening braking distances on snow by five to eight per cent, and drive-by noise has already been reduced to under 70 decibels for well-known tyre brands. "Today’s winter tyres need not be any louder than tyres without M+S labelling", points out Staude. The TÜV SÜD expert offers five tips to help drivers through the tyre changeover.
1. Labelling: Winter tyres showing "M+S" or "M&S" labelling meet the current German legal regulations for these products – yet the designation says little about their capabilities in dealing with ice and snow. Motorists are better advised to rely on the snowflake symbol, which TÜV SÜD recommends as a guideline; it guarantees a minimum of winter performance. Branded tyres fulfil these criteria.
2. Tread: Under German law, a tread depth of 1.6 millimetres is considered to be adequate even for winter tyres. "Far too little", warns Staude, who recommends a minimum of four millimetres. Drivers travelling to certain other countries require more tread depth as a matter of course; Austria specifies four millimetres for winter tyres, and Sweden three millimetres. But tread depth is not the only consideration: "Tyres wear less as they age, but the rubber compound they are made from grows harder. This in turn impairs their performance in winter." Staude recommends consulting a specialist for advice where tyres are more than six years old.
3. Changeover: Around one-quarter of car owners change their tyres themselves – and sometimes dangerous mistakes are the result. "Wheel nuts must be neither too loose nor – as very often happens – too tight", warns Michael Staude. Drivers obeying the principle of ‘as tight as possible’ can easily damage aluminium rims or even wheel hubs. A torque wrench is essential equipment for the procedure. And thorough cleaning of the wheel hub and rim areas in contact with the tyres is important – and often overlooked.
4. Monitoring system: From November, all new cars throughout the EU must be equipped with a tyre pressure monitoring system (TPMS). Some manufacturers already began to fit these systems on many of their car models some time ago. Depending on the system type, winter tyres may need sensors that activate a warning light on the dashboard when pressure is incorrect. The light may also stay on for a few kilometres after a tyre change, but this need not indicate a fault: "Some systems need this distance for recalibration", says Staude. Details can be found in the instruction manual.
5. Differences:The times when winter tyres required different driving styles, maximum speeds and air pressures from their summer colleagues are gone. On dry roads, the differences between seasonal models are now slight. Provided that road conditions permit, drivers can hit the same speeds as they do in summer – tyres approved for top speeds of 210, 240 or even 270 km/h are available.