What's the minimum legal tyre tread depth in the UK?

1.6mm across the central three-quarters of the tyre, around the whole circumference. Below that is a £2,500 fine and 3 penalty points per tyre.

Should I replace my tyres at 3mm or 1.6mm?

Many safety experts recommend 3mm — braking distances in the wet are significantly longer below this. The legal limit is 1.6mm but the safety margin is much better at 3mm.

How long should a set of tyres last?

Typically 20,000–40,000 miles depending on driving style, road type, alignment, and tyre brand. Premium tyres often last almost twice as long as budget options.

Do all four tyres need to match?

They don't legally have to, but they should match in size and load/speed rating, and ideally in brand and pattern on the same axle. Mixing aggressive and worn tyres front-to-back can affect handling.

Tyre Tread Depth UK: The Law, The 20p Test, and When to Replace

Tyres are the only part of your car that touches the road, and worn ones double or triple your stopping distance in the wet. UK law on tread depth is strict, the fines are eye-watering, and yet thousands of MOT tests fail on tyres every week. Here's the simple version.

The legal minimum: 1.6mm

UK law requires at least 1.6mm of tread across the central three-quarters of the tyre, all the way around. Below that, the tyre is illegal — even by a fraction of a millimetre. The penalty is brutal:

£2,500 fine per illegal tyre
3 penalty points per tyre
An MOT fail (obviously)
Insurance may be invalid if you have a claim

If all four tyres are below the limit, that's a potential £10,000 fine and 12 points — an instant driving ban.

The 20p test

You don't need fancy tools. Take a 20p coin and:

Insert it into the main central groove of the tyre
Check whether the outer band around the edge of the coin is visible
If you can see the outer band, your tread is below 1.6mm — replace immediately
Do the test in at least three places around the tyre (inner, middle, outer; and three points around the circumference)

It takes 30 seconds per tyre. Do it monthly.

The 3mm best-practice rule

Independent testing (including by Continental, MIRA, and TyreSafe) consistently shows that braking performance falls off sharply well before the legal 1.6mm limit. At 50 mph in the wet:

New tyres (8mm): ~25 metres to stop
3mm tread: ~35 metres
1.6mm tread: ~43 metres

That's almost an extra two car lengths between 3mm and 1.6mm — easily the difference between a near-miss and a collision. Many fleet and insurance experts recommend replacing tyres at 3mm.

How to check tyre age too

Even with good tread, rubber degrades. Look for a 4-digit DOT code on the sidewall — for example "2422" means week 24 of 2022. Tyres over 6 years old should be inspected for cracks and considered for replacement, regardless of tread.

Uneven wear — what it tells you

Worn in the centre — over-inflated
Worn on both edges — under-inflated
Worn on one edge only — wheel alignment is out
Feathered or scalloped patches — suspension worn (bushes, shocks)

Don't just replace the tyre — fix the underlying cause, or you'll wear out the new one just as fast.

Choosing replacement tyres

Stick to your car's recommended size (found inside the driver's door jamb). Premium brands (Michelin, Continental, Bridgestone, Goodyear) typically last 30–50% longer than budget alternatives — work out the cost per mile, not the upfront price.

Tyres are the cheapest insurance you can buy. £100 a corner can be the difference between a story you tell at the pub and an inquest.