What is the legal tyre tread depth and how do I check it?

Tyre tread depth

The legal minimum tyre tread depth in the UK and most of Europe is 1.6mm. It’s important that tyre tread depth is regularly checked because the less tread a tyre has, the poorer its performance. Safety experts recommend that drivers check their tyres at least once a month, ideally once a week or before they embark on a long journey.

How do I check my tyre tread depth?

Use a dedicated tyre tread depth gauge. You can buy these from around £5; a digital one (below) only costs about £10. Most are fast and accurate, although digital ones are likely to lose accuracy over time. When you check the tread depth, measure the tread nearest the car, the middle and the outer edge.

Tyre tread depth 

Spot your Tread Wear Indicators (TWI). Tyre manufacturers mould TWIs into the design of each tyre’s tread. They’re easily identifiable and made up of six or more small ribs across the bottom of the main tread grooves. These are usually 1.6mm to 2mm above the base of the groove. When the TWI is the same height as the tread, the tyre should be replaced.

Use a 20p coin (below). Place the 20p in the tyre groove at various places around the tyre and across the face of the tread. If the outer rim of the coin is visible above the tread, you need to buy a new tyre.

Tyre tread depth

How much tread do tyres start with?

Every tyre starts life with around 8mm of tread. The legal minimum is 1.6mm. However, independent tests show that the time it takes for a car to stop increases significantly once tread depth is below 3mm.

While you’re down there, perform a visual check

First of all you’ll need a torch and this involves getting down on the ground, so it’s probably better not to do it in your best suit. Look at the sidewall (the area of tyre perpendicular to the road). There should be no tears, cracks or bulges in it. All these can prompt MOT failures.

Inspect the wheel rims. These shouldn’t be dented or damaged to any great extent. Check the tread too, particularly for any screws or nails in it. The tread’s wear should be even. Your wheels are out of alignment if the tread on the inside is more worn than the outside or vice versa. Then take the torch and look on the inside sidewalls for tears and cracks.

Why tyre checks are vital

Tyres that are unroadworthy can land you with a fine of up to £2500 and three penalty points per tyre. Properly maintained tyres will also keep you and other road users safe and should help you to avoid accidents. If you’re ever in doubt about the condition of your tyres, always get them checked by a garage or tyre professional.