What Is the Legal Tyre Tread Depth in the UK?

The legal limit is 1.6mm

For cars in the UK, the law says your tyres must have at least 1.6mm of tread across the central three-quarters of the tread, all the way around the tyre. The outer edges are not part of that measurement, but the middle section must be legal around the full circumference.

That means one bald patch is enough to make a tyre illegal, even if the rest of it looks fine. Uneven wear is common, so it is worth checking all the way round and across the width, not just in one spot.

The penalties for illegal tyres

Driving on a tyre below the legal limit can bring a fine of up to £2,500 and 3 penalty points. That is for each tyre, so four worn tyres could mean far more points than you can afford to lose.

Tread depth is not the only rule. A tyre with a cut, a bulge in the sidewall or exposed cords is also illegal, whatever the tread looks like. Tyres are checked at every MOT, and worn or damaged tyres are a fail.

How to check your tread at home

Most tyres have small raised bars moulded into the bottom of the main grooves, called tread wear indicators. When the tread has worn down level with those bars, the tyre is at the legal limit and needs replacing.

You can also try the 20p test. Put a 20p coin into the main grooves in a few places across the tyre and around it. If you can see the outer band of the coin, the tread is getting low and it is time to have it measured properly. A cheap tread depth gauge from any motor factor gives you an exact reading.

Why 1.6mm is not the target

The legal limit is the very least the law allows, not the point where a tyre stops working well. The grooves are there to clear water away from under the tyre. As the tread gets shallower, there is less room for that water, so the tyre grips less in the wet and the car takes longer to stop.

That is why we suggest thinking about new tyres well before they reach 1.6mm, especially going into autumn and winter. Old rubber can also harden and crack with age, even if the tread is still deep, so it is worth looking at the sidewalls on a car that does few miles.

Do not forget the spare, if your car has one. It needs to be in good condition and at the right pressure too, because the day you need it is rarely a convenient one.

What uneven wear is telling you

If one edge of a tyre is wearing faster than the other, the alignment is likely out, often after a knock from a kerb or pothole. Wear down the middle can mean the tyre has been run over-inflated, and wear on both edges can mean it has been run soft.

Fixing the cause matters as much as fitting the new tyre. Otherwise the new one will wear the same way and you will be back sooner than you should be.

Get your tyres checked in Walsall

Pop in and we will measure your tread, check the tyres for damage and look at how they are wearing. If you need new tyres, we will tell you what fits your car and give you a clear quote before any work starts, and we can check the alignment while it is with us.

Call us on 01922 682200 or book online. We are at 45 High Street, Pelsall, WS3 4LT.