Tyre tread depth and tyre safety checks | RAC Drive (2024)

Checking your legal tyre tread depth is one of the most important checks you can make on your car.

The tyresare the only contact point between your vehicle and theroad. If your tyres are past their best then thesafety of your vehicle will be compromised.

Driving a car with bald tyres can risk a fine of £2,500 and three penalty points. That’s per tyre, too. If all four tyres are worn below the legal limit, you could potentially lose your licence and face a £10,000 fine.

Read on to find out how to check your minimumtyre tread depth and ensure you stay safe and legal on the road.

Thelegal tyre tread depth for cars in the UK and Europe is 1.6mmacross the central three-quarters of the tyre. By law, the tread depth must meet this minimum requirement across its complete circumference.

Bald tyres are one of the most common reasons for MOT fails, which is why it's essential that you get into the habit of checking your car's tyres regularly.

If you are not confident checking your car's tyres yourself, you can arrange for it to be checked by a mobile mechanic or local garage.

Tyre and safety experts believe the 1.6mm legal minimum is insufficient to guarantee safety – most recommend a minimum tread depth of 3mm for tyre replacement.

Tests by UK technical organisation MIRA found that, once tyres are below 3mm, stopping distances increase dramatically.

The difference in wet braking distance between a tyre worn to 3mm and one worn to 1.6mm can be as much as 44%.

Worn tyres are particularly dangerous in the wet because a tyre’s tread helps disperse water away from the contact patch between tyre and road.

If there’s less tread depth, less water can be shifted, increasing the risk of aquaplaning and losing grip.

In heavy rain, each tyre can shift one gallon of water every second, illustrating just how hard tyres work.

Simply put, deeper tread means they can work better, improving grip.

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Tyre tread depth has to be above 1.6mm to be legal. This must be the case for the middle three quarters of the tyre.

There are three ways to check this:

The 20p test is a simple, quick and easy way of checking the tyre tread of your car's wheels.

Just take a 20p coin and insert it into the tread grooves on the tyre.

If you can't see the outer band on the coin, your tyres are above the legal limit.

However, if you can see the band and that section of the coin is still visible, your tyres could be unsafe and require professional inspection by a mechanic.

We suggest drivers conduct the 20p test around every two weeks and before long journeys.

Checking tyre tread with tyre tread wear indicators

Some tyres will have indicators embossed on the tyre wall itself, usually with a line or arrow which is positioned somewhere below the outer tread.

If the tyre is flush with these, it is below the legal limit and needs replacing.

Checking tyre tread witha tyre tread depth gauge

These are purpose made tools that quickly measure the depth of an individual tyre groove.

READ MORE: How to check your car's tyrepressure

Driving with tyres that have a tread below the legal limit - or even worse, are bald - is dangerous.

It can put you and other motorists at risk.

If you are involved in an accident and the car you are driving has illegal or bald tyres, you should be aware of the consequences.

Any insurance claim as a result of an accident could be invalidated, so potentially your insurer won't pay out any money any repairs needed to your vehicle.

However, driving with dangerous or defective tyres also puts drivers at risk of a fine ofup to £2,500 and three points on their license.

That is per tyre, so four illegal tyres could mean a fine of £10,000 and 12 penalty points.

You can buy tyre tread gauges that help you assess the tread depth of the tyre, plus you can also get more basic colour-coded tools that let you know if a tyre is legal or not at a glance.

For more information about tyres read our complete guide to tyre buyingor our complete guide to tyre safety and maintenance.

For complete piece of mind, you can also check out our breakdown cover and European breakdown cover products today.

ALSO: Learner driver insurance - from 2 hours to 5 months

If your tyre tread is below or neat the legal limit, we would recommend that you purchase a replacement tyre. Head over to RAC Tyres where we sell everything from budget to premium brands.

Tyre tread depth and safety - FAQ

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