Key takeaways
- The UK legal minimum tyre tread depth is 1.6mm across the central three-quarters of the tread, all the way around the tyre.
- The same 1.6mm limit applies to cars, light vans and most light trailers; some larger commercial vehicles have a 1mm rule.
- Driving on an illegal tyre risks a fine of up to £2,500 and 3 penalty points per tyre, according to gov.uk.
- A tyre below 1.6mm is an automatic MOT failure, and it is one of the most common reasons cars fail.
The law on tyre tread is short but strict, and getting it wrong is expensive. This guide focuses on the legal side: the exact limit, where on the tyre it is measured, what counts for vans and trailers, how it affects your MOT, and the penalties you face if you ignore it. For the practical method of checking your tread at home, see our step-by-step guide linked below.
What is the legal tyre tread depth in the UK?
The legal minimum tyre tread depth in the UK is 1.6mm, measured across the central three-quarters of the tread and around the complete circumference of the tyre. This is set out in the Highway Code (rule 89) and the Road Vehicles (Construction and Use) Regulations. Any tyre below 1.6mm in that zone is illegal to use on a public road.
The figure is a legal floor, not a safety target. Most manufacturers and safety bodies advise replacing well before it. But for the purposes of the law and your MOT, 1.6mm is the line you must not cross.
Where on the tyre is tread depth measured?
Tread depth is measured in the main grooves across the central three-quarters of the tyre's width, and the limit must be met around the whole circumference. The outer quarter on each shoulder is excluded, but the central band must keep at least 1.6mm everywhere. If any part of that zone drops below the limit, the tyre fails.
This matters because tyres rarely wear evenly. A tyre can look fine on the outside while the inner edge has worn smooth, often a sign of an alignment or pressure problem. That is why checking at the inner, middle and outer grooves, and at several points around the tyre, is the only reliable approach.
Does the legal limit differ for vans and trailers?
For cars, light vans and most light trailers the legal minimum is the same 1.6mm across the central three-quarters. The 1.6mm rule covers vehicles up to 3,500kg, which includes the typical work van. Some heavier commercial vehicles and certain larger vehicles have a lower 1mm requirement, but that does not apply to ordinary cars and vans.
Caravans and trailers are easy to overlook because they sit unused for months, yet they must meet the same tread standard when towed. Fast Tyre covers cars, vans, 4x4s and caravans, so the 1.6mm limit is the one to apply across everything we work on. If in doubt about your specific vehicle weight class, treat 1.6mm as the safe limit.
Is worn tread an MOT failure?
Yes. A tyre with less than 1.6mm of tread across the central three-quarters is an automatic MOT failure under the DVSA MOT testing manual. Worn and damaged tyres are consistently among the most common MOT failure items, alongside lighting and suspension faults, which makes a pre-MOT tread check one of the easiest ways to avoid a retest.
The tester also fails tyres for cuts over 25mm or 10% of the section width, bulges, exposed cords, and incorrect tyre sizes or types fitted across an axle. So tread is not the only tyre item checked, but it is the one drivers most often get caught out by.
What are the penalties for illegal tyres?
Driving with a tyre below the legal tread depth is an offence carrying a fine of up to £2,500 and 3 penalty points per tyre, according to gov.uk. Because the penalty is per tyre, the numbers escalate fast: four illegal tyres can mean up to £10,000 in fines and 12 points, which is enough to lose your licence.
Beyond the fine, an illegal tyre can invalidate your insurance after an incident and leaves you legally responsible if worn tyres contribute to a collision. The financial and safety case for staying above the limit is overwhelming.
| Vehicle type | Legal minimum | Measured across |
|---|---|---|
| Cars and 4x4s | 1.6mm | Central three-quarters, full circumference |
| Light vans (up to 3,500kg) | 1.6mm | Central three-quarters, full circumference |
| Caravans and light trailers | 1.6mm | Central three-quarters, full circumference |
How to stay on the right side of the law
The simplest way to avoid all of this is a regular tread check and replacing before you reach the limit. If you want the practical method, our guide on how to check your tyre tread depth covers the 20p test and gauges. Knowing the numbers on your tyre also helps you buy the right replacements. If a tyre is at or below 1.6mm, do not keep driving on it — our mobile tyre fitting service comes to your home, work or the roadside across London and central England and fits legal tyres on the spot.
Frequently asked questions
It is 1.6mm across the central three-quarters of the tread, measured around the entire circumference of the tyre. This applies to cars, light vans and most light trailers under the Highway Code and Construction and Use Regulations. Below 1.6mm the tyre is illegal.
No, for light vans up to 3,500kg the limit is the same 1.6mm across the central three-quarters. Only some larger commercial vehicles have a lower 1mm requirement, so for a typical work van you should treat 1.6mm as the legal minimum.
Yes. A tyre below 1.6mm across the central three-quarters is an automatic MOT failure under the DVSA testing manual. Worn tyres are among the most common failure items, so a quick tread check before your test can save a retest fee.
Up to £2,500 and 3 penalty points per tyre, according to gov.uk. Because it is applied per tyre, four illegal tyres can mean up to £10,000 and 12 points, which is enough to put you over the threshold to lose your licence.
Legally you can use a tyre down to 1.6mm, but most manufacturers and safety bodies recommend replacing at around 3mm because wet grip drops off sharply below that. Replacing early is safer and avoids any risk of dropping below the limit between checks.
It can. If illegal tyres contribute to a collision, an insurer may reduce or refuse a claim and you could face prosecution. Keeping tyres above the legal limit protects both your cover and your liability if the worst happens.