The legal minimum tread depth for car tyres in the UK is 1.6 mm across the central three-quarters of the tread, around the entire circumference of the tyre.

Quick Scoop: The essentials

  • For cars, light vans and light trailers: minimum legal tread depth is 1.6 mm.
  • This 1.6 mm must cover:
    • The central three-quarters of the tyre’s width, and
    • The whole way round the tyre (its full circumference).
  • Below 1.6 mm, the tyre is classed as “bald” and is illegal to use on the road.

Other vehicles (for context)

  • Motorcycles, large vehicles and passenger-carrying vehicles generally have a lower legal minimum, often 1 mm in the UK, again across the required band of tread.

Safety angle (not just the law)

Even though 1.6 mm is the legal minimum, many safety bodies and motoring organisations recommend changing tyres at around 3 mm, because braking distances in the wet increase significantly as tread wears down from 3 mm to 1.6 mm. One study found tyres at 3 mm can have roughly 25% better wet performance than those at 1.6 mm, which can mean several extra metres of stopping distance.

Quick example: what this means in practice

Imagine you’re driving in heavy rain on the motorway. With healthy tread (around 3 mm), your tyres can clear more water and keep better grip, so you stop sooner in an emergency. With tyres worn down to just above 1.6 mm, you might still be legal, but your car could travel a full car length or more further before stopping, which can be the difference between a near miss and a collision.

TL;DR: Legal minimum for car tyres: 1.6 mm across the middle three- quarters of the tread, all the way round the tyre—but for safety, think about changing them closer to 3 mm instead of waiting for the legal limit.

Information gathered from public forums or data available on the internet and portrayed here.