Winter tyres unsuitable for summer conditions – Bridgestone

While winter tyres are still more or less a niche product in the UK – Bridgestone says only around eight per cent of motorists drive on winter tyres – across Europe this figure is much higher. Bridgestone shares that a study IPSOS conducted for it in 2014 shows 43 per cent of European drivers change over to winter tyres for the cold season, with usage rates increasing the further north and east you travel. A number of drivers succumb to the temptation of keeping their winter tyres fitted all year round, and doing so is perfectly legal – yet few realise the extent to which this can compromise their vehicle’s braking performance.

Tests carried out by Bridgestone show that the braking and handling performance gap between summer and winter tyres can vary in warmer weather by between eight and 30 per cent, depending on road conditions and temperature. In wet weather and an ambient temperature of about 30°C, a vehicle fitted with good quality summer tyres has a braking distance up to 30 per cent shorter than a vehicle fitted with winter tyres. In certain conditions, this difference can equal two car lengths.

The difference lies in the compound. The high silica content of a winter tyre compound helps it stay soft and flexible in cold conditions, providing (together with a winter tread pattern) traction and grip in low temperatures on dry, wet and icy surfaces. But as the temperature rises, winter tyres lose this advantage, grip declines and the tread starts to wear faster. On the other hand, the harder compound used in summer tyres does not become too soft and sticky on hot roads, which means they provide better all-round performance than winter tyres in higher temperatures, particularly in braking and handling, wear resistance, rolling resistance and fuel economy.

“If you’re tempted to keep your winter tyres on through the summer, the advice from Bridgestone is simple: don’t! The fact is, only summer tyres can give you the safety and performance you need in warmer weather,” comments Jake Rønsholt, managing director of Bridgestone Europe’s Consumer business unit.

To emphasise the difference between summer and winter tyre performance during the warmer months, Bridgestone has produced videos that show comparative performance in dry braking, wet braking and slalom tests.