SRSA warns that a combination of smooth tyres and high speeds can result in a complete loss of adhesion to the road’s surface, causing aqua-planning, with possible tragic consequences, particularly in wet weather conditions.
Motorists should remember, even with new or barely worn tyres, to reduce their speed in the wet and increase their following distance from the car in front. This is particularly valid after a long dry spell when rubber crumb, diesel fuel and oil, together with industrial fall-out absorbed by the tar, will rise to the road’s surface to form a slippery film before it is washed away.
The dangerous practice of regrooving tyres, which consists of cutting a pattern into the tread, deeper than the original tread, in order to extend tye life should be avoided at all costs. Regrooving the tyre has the effect of exposing the tyre casing, breakers or belts, which can cause the tyre to fail, increasing the risk of causing a major traffic accident.
The South African Road Traffic Act prohibits the use of a tyre, which is so worn or damaged that the cord or fabric used in its construction is exposed. The Act also states that the tyre tread should be clearly visible and must be at least one-millimetre deep around the entire circumference of the tyre. This minimum tread depth (MTD) legislation aims to protect the motoring public and pedestrians from the dangers of badly worn, smooth or near smooth tyres, especially in the wet. Dunlop recommends 1.6mm tread depth as a professional standard.
It is the tyre’s tread that displaces water to provide the grip on the road. Smooth tyres’ wet road grip decreases dramatically as speed increases. The stopping distance required will also increase as the tread pattern wears down. At 120km/hour, under wet weather conditions, the road grip of a new tyre can drop to 80% while that of an almost smooth tyre plummets to 10%*. Also, with new tyres the stopping distance at normal city speeds on a wet road is about 17 metres. At a recommended 3mm tread depth this stopping distance increases to 20 metres and at 1,6mm, still above the current minimum tread depth, the stopping distance is almost 32 metres, which is the length of eight cars.
In an effort to promote tyre safety and keep the public informed of best practice methods, SRSA has developed a series of innovative tyre care video clips aimed at promoting education and safety in a manner that can be easily understood by a diverse audience.
Currently playlisted on the YouTube channel under Dunlop Tyres SA, the vibrant and contemporary clips have an easy-going retro appeal. The clips take the viewer through some of the basic tyre guidelines detailing the reasons why tyres should be balanced, aligned and rotated regularly, as well as explaining tread depth indicators, sidewall markings and the dangers of incorrect inflation. There’s even a video detailing how to change a tyre.
Check out the "tyre tips" playlist under the YouTube channel Dunlop Tyres SA, or follow this link: http://www.youtube.com/watch?v=gA9LS-4HW4E&list=PLIG6COHcWFl9Iy_tbFrWwNq8AjOi2QQ-t
So, when travelling in wet and rainy conditions, ensure that you have a safe and legal tread depth on your tyres and keep a good following distance - after all, it could mean the difference between getting to your destination or not getting there at all!
*In a vehicle under test conditions