How to check tyre tread depth for safe and legal driving

When it comes to road safety, ensuring that your car tyres are in the best possible condition is one of the most important things you can do.

So what is the required tyre tread depth? How is it checked? And what are the risks if you don’t perform these checks?

We’ve answered your questions below…


What are tyre treads?

Tyre treads refers to the grooves that run along the circumference of your car tyres. These grooves help to disperse water away from the contact points of the tyre, improving grip and allowing you to drive more safely.


What is the legal tyre tread depth in the UK?

The minimum tread depth required for car tyres in the UK is 1.6mm. This tread depth must run across the central three-quarters of the tyre.

However, this is the bare minimum requirement and isn’t sufficient for long-term use. Here at JCT600, we will mark your tyres as red at 3mm in accordance with manufacturer guidelines.

What are the risks of not checking your tyre tread depth?

If you don’t check your tyre treads and have enough depth, then you could be at risk of:

  • An increased stopping distance – Imagine that you’re travelling in your car at 50mph on a rainy day. With the minimum legal tyre tread depth of 1.6mm, it would take around 39.5 metres to come to a stop when braking. With 0.8mm of tread, this increases to 53.1 metres.
  • Aquaplaning – In wet conditions, your tyres may lose contact with the road surface and instead travel on top of the surface of the water. When this happens, you won’t be able to brake, steer or accelerate properly.
  • Increased fuel consumption – The shallower your tyre tread depth, the harder your car must work to put its power to the ground.
  • Penalty points and a fine – Besides the risk of having an accident, you may also receive three penalty points and a fine of up to £2,500 (per tyre!) for having worn tyre treads.

It is the car owner’s responsibility to ensure that their tyres are safe and legal to drive on the road – not just for your own safety, but for the safety of others too.

How do you measure tyre tread depth?

Knowing how to check your car’s tyre tread depth – or having someone else check it for you – could save your life in the future.

How to check your tyre tread with a coin

The ‘20p test’ is a quick and easy way to find out if your tyres are under the minimum legal tread depth of 1.6mm.

Simply take a 20p coin and place it into the main tread groove of your tyre. If the outer band of the 20p is not visible and it slots within the groove, then your tread is above the legal limit.

However, if the outer band of the coin is visible, then your tyres may be illegal and unsafe to drive.

how to check tyre tread with a 20p coin

Using a tyre depth gauge to check your tyres

If the 20p coin trick isn’t reassuring enough for you, then you can use a tyre tread depth gauge (DTG) to measure the depth of an individual tyre groove.

You can also buy combined pressure and DTG gauges – or kits that supply both separately – for your convenience.

Checking the tyre tread wear indicators

Look out for these small bars, which are moulded into the treads in several places around the circumference of the wheel. If these are clearly visible at the surface of the tyre, then you’ll need to replace it.

How much tread is on a new tyre and how long should it last?

A new tyre should have around 8mm of tread before use. The longevity of your tyre largely depends on how well you treat it, from avoiding things like heavy braking to rotating your tyres regularly and maintaining consistent and adequate tyre pressure.

If you follow these tips, then you can expect your tyre treads to last you from 30,000 to 60,000 miles.

Check your tyre tread depth for free with JCT600

For the most accurate indication of how safe your tyre treads are, we recommend that you have your tyres checked professionally by one of our qualified technicians. We carry out FREE Tyre Checks at all our dealerships.

> Book your free tyre check

> Browse our list of dealerships

> Buy replacement tyres for your car

In summary, checking your tyre tread depth is quick and simple and doesn’t have to cost you any money. However, the effect it can have could be enough to keep you safe (and within the law) on the roads.

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