The legal minimum tyre tread depth in the UK is 1.6mm. That figure applies to cars, vans and light trailers up to 3,500kg, and the tread must meet it across the central three-quarters of the tyre's width, all the way around the wheel. This is set out in the law on tyre safety (GOV.UK) and reflected in Highway Code rule 89.
What the 1.6mm rule actually means
Tread is the grooved rubber that grips the road and clears water. As it wears down, stopping distances grow and the risk of aquaplaning rises sharply. The 1.6mm minimum is a legal floor, not a target. Tyre-safety charity TyreSafe and most manufacturers recommend changing tyres at around 3mm, because braking performance drops off noticeably between 3mm and 1.6mm, especially in the wet.
How tread depth is measured
The 1.6mm is measured in the main grooves across the middle 75% of the tyre, around the complete circumference. A tyre can be legal in one spot and illegal in another if it is wearing unevenly, which is common with poor wheel alignment or incorrect pressures. Garages use a tread depth gauge; at home you can use the 20p test as a quick check.
The penalties for illegal tyres
Driving with a tyre below the legal limit can cost you up to £2,500 and 3 penalty points per tyre. With four illegal tyres that is a potential £10,000 fine and 12 points, which is enough to lose your licence. Illegal tyres can also invalidate your insurance after an accident.
- Tread below 1.6mm – illegal, MOT failure, fine and points.
- Cuts, lumps or bulges – illegal regardless of tread depth.
- Wrong size or type mixed on an axle – can also fail the MOT.
What to do if your tyres are close to the limit
Don't wait for the MOT. If a quick check shows you're near 1.6mm, get the tyres replaced. Our mobile tyre fitters come to your home, work or the roadside across London and Birmingham, so you never have to drive on a borderline or illegal tyre to reach a garage. You can book in about two minutes with a £10 deposit.
