Blog / Checking tyre tread

Tyres & Brakes · 3 min read

How to Check Your Tyre Tread Depth at Home

Checking tread depth takes under a minute per tyre and needs no special tools, just a 20p coin, which makes it one of the easiest checks to genuinely do regularly rather than put off.

The legal minimum

UK law requires at least 1.6mm of tread depth across the central three-quarters of the tyre, all the way around. Below that is an MOT failure and a driving offence in its own right, with penalty points and a fine per illegal tyre, not per car.

The 20p test

1. Insert a 20p coin into the main tread grooves
2. Check at several points around the tyre, not just one spot
3. If the outer band of the coin is still visible, tread is getting close to the legal limit and worth having measured properly
4. If the coin's outer band disappears into the groove, tread is comfortably above minimum

Why the legal minimum isn't really the target

Braking distance in wet conditions increases significantly as tread wears down, well before it reaches the legal limit. Many safety organisations suggest replacing tyres nearer 3mm rather than waiting until 1.6mm, particularly for winter driving, since the difference in wet grip between 3mm and 1.6mm is larger than most drivers expect.

Check more than one spot

Tyres can wear unevenly, so a single measurement at one point can miss a genuinely worn area elsewhere on the same tyre. Checking at three or four points around the circumference, and comparing the inner and outer edges, catches uneven wear that a single check would miss entirely.