Tyre Tread Depths

Tyre Tread Depth And Safety Checks

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

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 3 penalty points for a worn tyre will?, and that is for every tyre below the legal minimum, so upto £10,000 fine and 12 penalty points which means losing your licence is likely.

What is the legal minimum tyre tread depth?

The legal minimum tyre tread depth for cars in the UK 1.6mm across the central three-quarters of the tyre.

What is the expert-recommended 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.

Different Ways To Check

The 20p test

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

Use 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. This is not a fool proof method and professional advice should be sought if in doubt.

Tyre tread wear indicators

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. Here is Phill explaining how to use the tool.

We will happily inspect your tyres for free and let you know if they are legal to use or if replacement is required, just call or message us to book in.

This post is for information only, the sole responsibility lies with the vehicle driver to ensure the vehicle is properly maintained and the driver must ensure it is used on a road in a roadworthy condition. If you are ever in doubt then contact a suitably trained professional to assist you.