If you drive a typical number of kilometres, somewhere around 19,000 to 24,000 kilometres annually, a tyre's tread will wear out in three to four years, long before the rubber compound does. But if you drive much less than that, or have a car that you only drive on weekends, aging tyres could be an issue.
What happens to a Tyre as it ages?
As the tyre ages, oxidation causes cracks to develop over time, appearing on the surface and inside the tyre as well. 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.
Every tyre that's on the road long enough will succumb to age. Tyres that are rated for higher mileage have antiozonant chemical compounds built into the rubber that will slow the aging process, but nothing stops the effects of time on rubber.
What is the cut-off age of a Tyre?
Carmakers, tyre-makers and rubber manufacturers differ in their opinions about the lifespan of a tyre. Most vehicular authorities of the world have no specific guidelines on tyre aging and defers to the recommendations of carmakers and tyre manufacturers.
Many automakers, including Ford, Nissan and Mercedes-Benz, ask owners to replace tyres six years after their production date, regardless of tread life. Tyre manufacturers such as Continental and Michelin say a tyre can last up to 10 years provided you get annual tyre inspections after the fifth year.
The Rubber Manufacturers Association says there is no way to put a date on when a tyre "expires" because of such factors as heat, storage, under-inflation and conditions of use can dramatically reduce the life of a tyre. Here's more on each of these factors:
Numerous researches have found that tyres age more quickly in warmer climates. Environmental conditions, such as exposure to sunlight and coastal climates, have been observed to hasten the aging process. People who live in coastal states and other areas with warm weather should keep this in mind when deciding whether they should retire a tyre.
This applies to spare tyres and tyres that are sitting in a garage or shop. A tyre that has not been mounted and is just sitting in a tyre shop or your garage will age more slowly than one that has been put into service on a car. But it ages nonetheless.
They usually don't see the light of day, but they're still degrading with time. If the tyre has been inflated and mounted on a wheel, it is considered to be "in service," even if it's never been used. And if a truck's spare is mounted underneath the vehicle, it's exposed to heat, dirt and weather — all reasons to plan on replacement.
Conditions of use
This refers to how the tyre is treated. Is it properly inflated? Has it hit the pavement curb too many times? Has it ever been repaired for a puncture? Tyres on a car that's only driven on the weekends will age differently from those on a car that's driven daily on the highway. All these factors contribute to how quickly or slowly a tyre ages.
Proper maintenance is the best thing a person can do to ensure a long tyre life. It is important to maintain proper air pressure in tyres, rotate them regularly and get routine inspections