Why motorists should replace old or worn tyres

There are an untold number of people driving around on the roads today with unsafe tyres. An investigation by price comparison website Confused.com found that over one-fifth of all UK motorists could have unsafe tyres. This is the equivalent of 8 million cars, in just one country!

Manufacturers recommend that people change their tyres when the tread depth reaches below 3mm, but the study found that 21% of the 1,000 cars examined had less than 3mm tread depth on at least one wheel. 

Worse still, the legal minimum tread depth is 1.6mm, but Confused.com’s investigation discovered that 3% of cars had tyres below this legal limit. Across the country, this would equate to a massive 1.4 million motorists. Organisations such as the Royal Society for the Prevention of Accidents recommend that people replace tyres as soon as they get to 3mm tread depth, and long before they hit 1.6mm, as when tyre tread wears down to a low level, the tyres can no longer provide an effective grip on the road.

This lack of grip poses a risk to drivers, other road users, and the general public. In the UK, in 2016 alone, 120 people suffered serious injuries in traffic accidents where defective, illegal, or under-inflated tyres were deemed to be a contributory factor, and eight people lost their lives, government data shows.

Why should motorists get their tyres replaced when the tyre tread is shallow?

• Tyres are more dangerous when the tread is worn. Tyre tread is intended to improve a car’s grip, and will pump water away from the tyre during wet conditions. When the tyre tread depth gets below 3mm, the tyre stops performing this function as effectively as it can, which can lead to aquaplaning, will increase the time it takes to stop, and will also make the tyre more vulnerable to a blowout. Replacing tyres in time is therefore very important for public safety. It’s estimated that replacing old tyres will improve car safety for over 65,000 miles. However, motorists should speak with their tyre manufacturer to see when their tyres should be changed, and should check regularly for any defects.
• Car insurers may not pay out in the event of accidents. If accident investigators discover that a car’s tyres were not roadworthy and that they were not replaced when worn, this information will be passed to insurers. In some instances, this can lead to insurers voiding car accident claims, leaving the driver with potentially insurmountable bills. This is especially the case in the event of personal injuries; coping with the cost of a personal injury claims without an insurer’s help can be ruinous.
• Improved performance. The safety implications of worn tyres is reflected in decreased performance, too. Replacing worn tyres will not only improve stopping distance, but will also improve cornering and acceleration by boosting the amount of power the vehicle transfers to the road surface.
• Improved fuel efficiency. The improvements in performance contribute to improved fuel efficiency, making it cost-effective to fit new tyres when the old ones are worn down. While old tyres mean a car will struggle to put all of its power into the ground due to reduced friction on the road, new tyres will help get the vehicle back to optimal performance.
• Better driving in all weather conditions. The improved grip offered by new tyres will enhance a car’s ability to cope with adverse weather conditions and can make the vehicle nicer to drive overall. Replacement tyres can reduce noise and prevent rumbling on uneven road surfaces, and can cope with snow, mud, and other slippery surfaces much better than worn tyres.

Old tyres

Tyres can need replacing because of general ageing. With old tyres, the tread could still be above the 3mm guideline, but due to the tyre’s age they could still be unsafe for use. Manufacturers use anti-oxidising chemicals in tyre rubber to slow down the ageing process, but there’s nothing that can stop it, and over time, the risk of tyre failure increases.

As it’s impossible to tell how long any individual tyre will be safe for, it is up to motorists to determine if their tyre is still roadworthy.

Many people think that stationary cars, or other vehicles that are stored for long periods of time, will have safe tyres as long as the tread depth remains legal. However, when cars are in motion, anti-ageing compounds are pushed through the rubber to prevent age-related decline, but when cars, motorhomes, caravans and classic cars are stationary for prolonged periods, this process does not happen. This is also a concern for spare wheels and any other tyre that remains out of use for a long time. 

Factors that can cause premature tyre ageing

Some of the other factors that can contribute to tyres ageing before their time include:

• The use of a number of cleaning chemicals that are associated with damaging the chemicals in the rubber
• Using the tyre near coastal areas or in other saline environments
• Typical car usage
• The area the vehicle or tyres are stored
• The typical road conditions when the tyres are used
• The motorists’ driving style.

Some of the indicators that a tyre needs replacing due to ageing include:

• The tyre tread becoming distorted
• Cracking on the tyre’s side wall
• Any other distortion of the tyre.

Driving with unsafe tyres can also leave you at risk of a motoring conviction. The maximum penalty for driving with an illegal tyre is £2,500 per tyre and three penalty points on your license, which means a car with all four tyres having less than the required tread depth could see the owner fined £10,000 and losing their licence.

Do motorists know the rules?

GoCompare.com’s research found that nearly two-thirds (61%) of motorists are unaware of the minimum tyre tread depth of 1.6mm, and more than half (55%) don’t know how to check their tread depth. 

Despite the lack of knowledge, a massive 4% of UK drivers have had auto collisions involving unsafe tyres, and 11% have never had their tyres checked. Of those who have had their tyres checked, 16% only have this done when they have an MOT.

It is clear that a large number of motorists are unfamiliar with legislation relating to tyre tread depth. Fortunately, this is one of the checks in a standard MOT, and cars with unsafe tread depth will fail this test. Cars over three years old require MOTs annually, and during this test dangerously low tread depth will be identified.

How to check your tyre tread depth

Many tyre manufacturers use tread wear indicators, which are small markers within the tyre tread. As the tyre wears down from its original 8mm tread depth, it will eventually become level with the tread wear indicator, which means it should be changed. Some manufacturers, such as Continental, use two tread depth indicators; one is at 3mm and the other at 1.6mm, so you can tell when a tyre ought to be replaced and when you are legally obliged to do so.

An easy way to check the tread depth of your tyre is with a 20 pence piece. If it isn’t possible to spot a tread depth indicator, take the 20p coin and put it in the main tread channel. A 20p has an outer band running around it, and the emblem / Queen’s head in the middle. If any of the outer band of the coin is visible when it’s in the tread, the tyre is too shallow and is illegal to use.  Please ensure this test is repeated at various points on the tyre, and on all tyres.

Some motorists simply take their car to reputable tyre fitters to see if they need a replacement. Tyre replacement providers can offer peace-of-mind by using their expertise to determine if tyres are safe for use or not. 

However, with such a large number of UK motorists found to be driving with dangerous tyres, it is clear that a hazardous number of motorists do not check their tyres at all. The best way for other road users to protect themselves against these drivers is to ensure that their car is properly maintained, including their tyres, and that they practice defensive driving, for example by maintaining a good distance from the car in front, staying within the speed limit, driving in a manner that is appropriate for the road conditions, and paying close attention to the behaviour of other motorists. 

Keeping safe

To minimise the risks posed to themselves, their passengers and other road users, motorists should do the following:

• Change their tyres when the tread depth reaches 3mm as shown by tread depth indicators
• Check tyre pressure regularly, as over or under-inflated tyres are more likely to become damaged
• Inflate tyres to the recommended tyre pressure before any long journeys
• Visually inspect the tyre for signs of damage or wear and tear
• Immediately check tyres if any concerns arise, and
• Replace any damaged tyres immediately