A simple check can help drivers avoid a potential problem
Millions of motorists are falling foul of the rules due to one problem. Rafts of vehicles are failing MOTs due to simple tyre faults, with a recent Freedom of Information request revealing that 3.1 million individual tyre defects led to MOT failures between July 2023 and July 2024.
Experts at Scrap Car Comparison are now urging drivers to carry out one straightforward at-home check, which could be the difference between passing and failing the test. Data from YouGov in October showed that 60% of drivers confessed to only replacing their tyres when absolutely necessary, suggesting they could be driving on unsafe, worn-out tyres without knowing it. While tread depth is often discussed, many drivers neglect to consider the age of their tyres and the overall condition of the rubber, which can also pose safety risks.
Matt Clamp, customer service manager at Scrap Car Comparison, said: “MOT tests are something that can often fill car owners with dread. Tyres are an aspect of a vehicle that owners can easily inspect themselves, so there’s little reason why a car should fail for these faults.
“However, tyre perishing is something that is often overlooked. Even cars with low mileage aren’t immune to this, which often catches owners out. In fact, perishing can actually be accelerated due to inactivity.”
Why tyres fail MOTs
While it’s common knowledge that MOT tests scrutinise a tyre’s tread and depth, as well as any cuts and bulges, testers also look for signs of age-related wear and tear, such as cracking and degradation of the sidewalls and tread. Evidence of perishing can result in a minor warning, like an advisory, but could also lead to a failure if the level of degradation is severe.
Tyres naturally degrade over time due to factors like ageing, wear and tear, and exposure to elements like UV rays and heat. This causes the rubber compounds to weaken and become brittle, leading to cracking and an increased risk of bulges in the sidewall, as well as a loss of road grip.
Poor wheel alignment, incorrect tyre pressures and aggressive driving habits like harsh acceleration and braking can speed up this degradation process.
Contrary to popular belief, tyres that are driven less don’t necessarily last longer, as inactivity can actually hasten the rate of perishing. Regular use activates and disperses protective chemicals in the rubber compounds, which doesn’t occur if the tyres remain static, thus accelerating the ageing process.
Tyre code check
Every tyre will have a DOT code on the sidewall, which indicates the date of manufacture and can be a good indicator of whether it may be time for a replacement. The last four digits of the DOT code indicate the date of manufacture, with the first two digits showing the calendar week of production and the final two representing the year – for example, 1524 would mean the 15th week of 2024.
As a general rule of thumb:
Any tyres over five years old should be checked annually by a specialist
Tyres of 10 years old or more should be replaced, regardless of tread condition
Though five years is the age at which perishing is most likely to occur, tyres that have been exposed to high temperatures and UV rays, or have been left unused for long periods, are likely to perish faster. As well as checking DOT codes, vehicle owners should look out for visible cracks and fissures, which can often appear as a ‘cracked eggshell’ texture.
Matt advised: “Getting in the habit of regularly checking your tyres can help to avoid any last-minute panics before your MOT, and also help your tyres last longer. Perishing can occur faster if tyres aren’t inflated to the correct pressure, so checking this regularly could help avoid the need to fork out for new tyres as often. If possible, storing your car in a garage or out of reach of the sun will also improve the longevity of your tyres, but as this isn’t achievable for most drivers, just making sure you’re using your vehicle regularly will be beneficial.”