What Tyre Tread Depth Is Legal in the UK?

The legal minimum tread depth

The legal minimum tyre tread depth for cars in the UK is 1.6mm. It must be at least 1.6mm across the central three-quarters of the tread, all the way around the tyre. Drive on tyres below that and you risk a fine of up to £2,500 and three penalty points for each illegal tyre.

That rule applies to cars, light vans and light trailers. The law also covers the general condition of tyres, so a tyre with a deep cut, a bulge, or exposed cords can be illegal even if it has plenty of tread left.

The penalties for illegal tyres

The penalty is per tyre, which is what catches people out. One worn tyre could mean a fine of up to £2,500 and three points. If all four tyres are illegal, that could add up to £10,000 and 12 points, which is enough to lose your licence.

Worn or damaged tyres are also a common reason for an MOT failure, and if you are involved in an accident, illegal tyres could cause problems with your insurance claim. It is far cheaper to replace a tyre than to deal with any of that.

Why 3mm is the sensible limit

Tread is there to push water out from under the tyre so the rubber can grip the road. As the tread gets shallower, it clears less water, and the tyre is more likely to aquaplane and take longer to stop on a wet road.

Stopping distances show the difference clearly. On a wet road, a car on worn tyres can need noticeably more distance to stop than the same car on tyres with plenty of tread. That extra distance can be the gap between stopping safely behind a queue of traffic and running into the back of it, which is why checking your tread regularly is so worthwhile.

Tyre makers and road safety groups generally advise replacing tyres at around 3mm, because performance in the wet drops off quickly below that. If you do a lot of motorway driving, or you want to be sure of grip through a wet winter, 3mm is a much safer point to change them than 1.6mm.

How to check your tread: the 20p test

The easiest home check is the 20p test. Put a 20p coin into the main grooves of the tyre. If you can see the outer band around the edge of the coin, your tread may be close to or below the legal limit and the tyre should be checked properly straight away.

Do this in several places across the width of the tyre and at a few points around it, as tyres rarely wear evenly. You can also look for the tread wear indicators, small raised bars in the bottom of the main grooves. When the tread is level with those bars, the tyre is at 1.6mm and needs replacing.

For an exact reading, a tread depth gauge costs very little from a motor shop, or any tyre fitter can measure it for you in a minute.

Uneven wear is a warning sign

If one edge of a tyre is wearing much faster than the rest, the wheel alignment may be out, often after hitting a kerb or pothole. Wear on both outer edges usually points to under-inflation, and wear down the centre can mean over-inflation.

Remember to check the spare as well, if your car has one, because a spare with perished rubber or low pressure is not much help at the roadside. Age matters too. Rubber hardens and cracks over the years, even on tyres that have done few miles, so a tyre on a car that is rarely used can need replacing before its tread is worn out. The four-digit date code on the sidewall shows the week and year the tyre was made, so 3421 means the 34th week of 2021.

Uneven wear shortens tyre life and can affect how the car handles, so it is worth getting the cause fixed rather than just fitting new tyres and letting them wear the same way. Checking your pressures once a month helps your tyres last longer too.

Get your tyres checked in Walsall

If you are not sure how much tread you have left, or the 20p test worries you, bring the car in and we will measure your tyres and check for damage and uneven wear. We will tell you honestly whether they need replacing now or have life left in them.

Call MF Autocentre on 01922 636820 or book online to get your tyres and tracking checked in Walsall.