KNOW YOUR TREAD

The tread of the tyre is one of the most important components of the tyre, and the appearance is often one of the deciding points why people will buy a certain tyre or not.

The tread, or rather the lack of it, is usually the reason why a tyre has to be replaced, as it is the wearing surface and contact patch on the tyre.

Let us look at what it has to do:

The tread has to transmit the forces for acceleration, braking and then cornering from the vehicle to the road surface, so as to provide the necessary grip.

When you consider that most vehicles weigh in the order of 1500 kg, and are capable of speeds well in excess of our legal limit of 120 km/h, this is quite a tall order to ask of the tyre.

The tread has certain features, the most noticeable being the tread grooves. Contrary to popular belief, they do not disperse the water from the footprint, but are designed to hold water in them in order for the raised portion of the tread, or blocks, to make physical contact with the road. At speeds of around 120 km/h, there is no way that the water will channel itself through the tread grooves and come out of the side of a tyre.

To give you an idea as to how much water the tyre would have to process at 120 km/h, consider the depth of water at 2mm and the tyre size of 205/55 R16, each tyre would have to process nearly 12 litres per second – the equivalent of running your garden hose at full blast for 6 seconds.

If the depth of water is too much, the depth of the tread too little, or the speed of the vehicle too high, for the tread grooves to process this water, then aquaplaning will occur, and the tyres loose contact with the road, the rest will be history. It is not surprising then that tyre dealers can make good business the day after it has rained. Funny thing, human nature, the risks we take in an effort to get the best possible mileage out of our tyres.

So please remember to check your tyres regularly, in the interest of your safety and other motorists who travel our roads daily.