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, age 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 how old your tyre is.

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, 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 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 many will 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. 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 many new cars may not have a spare tyre!

Caravans and trailers

Damage through ageing is more common with caravans, trailers, horse boxes and other vehicles only used occasionally.

The National Caravan Council estimates there are circa 525,000 touring caravans, 327,000 caravan holiday homes and 174,000 motorhomes currently in use in the UK.

(Source: http://www.thencc.org.uk/)

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

The Caravan Club offers the following advice, which can also be used for trailers:

“As a general rule, it is advised that caravan tyres should ideally be replaced when 5 years old, and should never be used when more than 7 years old. This advice is borne out by the Club’s own research into caravan tyre failures, which confirms that the likelihood of a tyre problem increases after such age. Our research further suggests that tyres which need a high inflation pressure (say 50psi or more) require greater care still. Such tyres should be closely examined for signs of deterioration from 3 years old, and it would be strongly advised not to use them beyond 5 years old. It is not the case that all tyres over these ages will rapidly fail. However, the statistical likelihood of a problem occurring increases noticeably with age. Given the disruption to your holiday that a tyre failure could cause (let alone the risk involved), it is strongly recommended that you follow this guidance.”

(Source: http://www.caravanclub.co.uk/)

Further information on horse box tyre safety can be obtained from the British Horse Society website: (http://www.bhs.org.uk/)