Having worn tyres means the only contact patch between you and the road is past its best.
You could almost call it an accident waiting to happen.
If the safety risks don’t hit home, maybe the risk of a £2,500 fine and three penalty points for a worn tyre will?
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.
What is the legal tyre tread depth?
The legal tyre tread depth for cars in the UK and Europe is 1.6mm across the central three-quarters of the tyre, according to law.
The tread must meet this minimum requirement across its complete circumference.
What is the minimum tyre tread depth?
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.
How to check your car tyre tread
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:
How to check tyre tread depth – the 20p test
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 with a 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 tyre pressure
What happens if you have an accident on illegal/bald tyres?
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 of up 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 buying or 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.
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Tyre tread depth and safety - FAQ
- Is 2 mm tyre tread legal?
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.
- What is the legal limit for tyres to pass MOT?
The legal tyre tread depth in the UK is above 1.6mm in the middle three quarters of the tyre.
- How long does the average tyre last?
In terms of miles a tyre should last, there is a general acceptance with manufacturers, that tyres have a lifespan between 20,000 and 40,000 miles. However. this can vary if you tend to drive on more uneven and challenging surfaces. Even if you drive limited miles each year, tyres should be replaced every five or six years. Always ask your mechanic at your annual MOT about the safety of your tyres. It is important to remember that for the majority of vehicles, the front tyres wear quicker than the rear ones.
- What depth should tyres be?
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.
- What is the lowest legal limit for tyre tread?
The lowest trade depth for tyres is 1.6mm - which is a legal minimum. Industry experts recommend a minimum tread depth of 3mm for tyres.
- How long does it take for tyre tread to wear down?
Tyres wear down different depending on the road conditions and how often you use your vehicle. Manufacturers generally agree that they should be replaced every 20,000 to 40,000 miles. Your tyres should be checked every year during your vehicle’s MOT.
- What does 1.6 mm tread look like?
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.
