Tyre Ageing

Are your tyres past it?

Tyres are fantastically engineered products. They are the only thing keeping your car in contact with the road come rain or shine. However, like everything else, aging can take its toll on tyres, so it could be time to get yours checked by an expert, such as an NTDA member.

To help identify their age, all tyres display a coded date of manufacture and these codes are usually located in a ‘window’ on the tyre sidewall. The first two digits represent the week and the second two the year of manufacture, but if you are in doubt visit an NTDA member’s depot / centre to have an expert verify the age and condition of your tyre. However, please be aware, that it is not uncommon, for a tyre manufactured two years ago, for example, to be sold and fitted as new. Providing that the tyre has been stored in optimum conditions to preserve it, has not been exposed to the elements or previously fitted to a vehicle, it should be perfected safe and fit for purpose.

The NTDA recommends that tyres fitted to vehicles over 10 years old are checked for damage, wear and other signs of old age. Many NTDA members recommend that you have your tyres checked if you believe they are over 6 years old.

Tyres – working hard for you

Just because your tyre is 6, or even 10, years old does not automatically make it unsafe. As aforementioned, it may have been fitted two year after manufacture and was perfectly safe at the time of fitting, but it is still worth getting it checked, as tyres work very hard, day in, day out. Tyres should be checked regularly for signs of ageing, damage and tread wear.

Rubber compounds used in tyres contain anti-oxidising chemicals that help to slow down the natural ageing process of untreated rubber. However, tyres will always deteriorate with age, which increases the risk of tyre failure, and there are many ways in which this can be spotted:

  • Cracking/crazing on the side wall of the tyre, caused by its flexing;
  • Distortion of tyre tread;
  • Deformation of the carcass of the tyre;
  • There will also be a deterioration of the ride quality caused by vibrations through the tyre. This may signify the tyre’s performance has been affected by age and should be investigated as soon as possible;
  • Excessive or irregular wear can indicate problems such as misalignment – your NTDA expert will recognise the warning signs and recommend corrective action.

Motorists should be aware that as well as wearing out in use, tyres are degrading naturally through exposure to heat, sunlight (Ultraviolet/UV) and rain, chemicals, salts and incorrect storage. The amount of damage can also depends on the level of exposure and the severity of the weather.

Tread Depth – 3mm for improved safety. Regular examinations by both a tyre expert and the motorist should be carried out taking particular notice of tread depth and the aforementioned damaged side walls.

The spare tyre: out of sight…

Very few cars will run one set of tyres for 10 years, but some may still have a decade old tyre on board namely the all-too-often-forgotten spare.

Next time your tyres are checked, don’t forget to get the spare inspected if your vehicle still has one. The NTDA recommends that spare tyres over 6 years old should only be used as a ‘get you home’ emergency measure and then changed at the earliest opportunity.

However, motorists should also be aware that most new cars do not have a spare tyre or even a space to accommodate one!

Caravans and trailers

Damage through ageing is more common with caravans, trailers, horse boxes and other vehicles only used occasionally. Unlike the situation with cars, potential problems with caravan, trailer and horse box tyres are not caused by excessive use – just the opposite, in fact.

Caravans and trailers are often static for months, but although the tyres are not moving, they are still under load. Caravans are usually stored in the open, making tyres prone to ozone damage, with the aforementioned cracks or ‘crazing’ of the rubber. This process is then accelerated by the ultraviolet rays in sunlight.