Correct tread depth is vital to ensure that your car is controllable on wet roads. This is according to Romano Daniels, Bridgestone South Africa’s General Manager of Group Communications and Marketing.
“Many people think that the purpose of tread on tyres is to grip the road,” he said, “but it’s actually to disperse water on wet roads. If your tyres are worn, they might not be able to clear away standing water fast enough and the tyre will then begin to skim along the surface of the water. This is called aquaplaning or hydroplaning” he explained.
He said that aquaplaning was very dangerous because the tyre was no longer in contact with the road, meaning the vehicle could not be braked or steered. “Motorists in the summer rainfall areas of South Africa should pay careful attention to their tread depth to ensure proper traction in the sudden downpours which are common at this time of year,” he added.
The minimum allowable tread depth is 1mm over the entire surface of the tyre. If a tyre is fitted with a tread wear indicator (TWI), the tyre is no longer legal once the tread has worn level with the TWI. However, Daniels commented that a tyre worn down to these limits was unlikely to be able to disperse water effectively in wet weather.
“We recommend that you consider replacing your tyres once the tread depth has worn to three millimetres,” he said. “The tyre may still be legal at this point, but it will not be as resistant to aquaplaning as a tyre with deeper tread.”
He said that a tyre specialist would be able to measure the tread depth and advise whether the tyre should be replaced or not. He also urged motorists to reduce their speed when driving on wet roads and avoid patches of deep water. “Even a brand-new tyre can aquaplane if the vehicle is travelling at an excessive speed or there is too much water on the road,” he commented. “A combination of good tread depth, moderate speeds, and avoiding standing water can help protect you against aquaplaning,” he concluded.
Issued by Bridgestone South Africa on 11th November 2009
Keep it in mind that your insurance provider can reject your car insurance claim if your tyres are not roadworthy. See Car insurance claim can be rejected if vehicle tyres are not roadworthy!