Why worn tyres are a road hazard

BUYING new tyres can be a costly affair and most people put it off for as long as possible.

But vehicle owners need to realise that many accidents on our roads are caused by worn and old tyres.

So how do you know when it’s time to replace your tyres?

Pieter Niemand who is director of the Motor Industry Workshop Association (Miwa), a constituent association of the Retail Motor Industry Organisation (RMI), says most people rely on a tyre’s tread depth to determine its condition.

“But the rubber compounds in a tyre deteriorate over time, regardless of the condition of the tread.

“An old tyre can be just as hazardous as a tyre with worn tread,” Niemand said.

For some people, old tyres might never be an issue. “If you drive more than 19 000km annually, the tread will wear out in three to four years, long before the rubber compound does.

“But if you drive less than that, or have a car that you only drive on weekends for example, aging tyres can become an issue. “The age warning also applies to spare tyres and “new” tyres that have never been used but are old,” he said.

As with all products made using rubber, tyres will deteriorate with age, whether they are in use or not. Cracks in the rubber will begin to develop over time. They will appear on the surface and inside the tyre.

This cracking can eventually cause the steel belts in the tread to separate from the rest of the tyre. Improper maintenance and heat accelerate the process.

So how do you check the age of your tyres? Niemand said while car, tyre and rubber manufacturers differed in their opinions about the lifespan of a tyre, the DOT-code on the inside of the tyre provided information on the production date.

Tyres produced after 2000 have a four-digit DOT code instead of three. “The first two digits indicate the production week and the second two are the year,” he said.

Niemand said the South African climate definitely contributed to the aging of our tyres as exposure to sunlight, heat and especially coastal conditions were known for weathering rubber.

“This principle also applies to spare tyres and tyres that are sitting in a garage or shop. Consider how a spare tyre lives its life.

“If your spare is kept in the boot, it’s baking in a miniature oven all day.”

While most spare tyres never see the light of day, if a tyre has been inflated and mounted on a wheel, it is technically in service even if it’s never been used.

A tyre that has not been mounted and is just sitting in a shop or garage will age more slowly than one that has been put into service on a car. But it ages nonetheless. Niemand encouraged car owners to avoid buying used tyres and to check the date on all new tyres purchased.

“Don’t leave it until an accident happens. By then it will be too late and the consequences may be dire,” he warned.