What is the legal minimum tyre tread depth in the UK?

The legal minimum tread depth for cars (and light vans up to 3.5 tonnes and light trailers) is 1.6mm. This must be maintained across the central three-quarters of the tread width and around the complete outer circumference of the tyre. Motorcycle front tyres must have 1mm across ¾ of the width; rear tyres require 1mm across ¾ with visible tread on the remaining quarter.

How do I check my tyre tread depth?

Three methods: (1) Use a tread depth gauge — available from any motor factor for a few pounds and gives an accurate reading. (2) The 20p coin test — insert a 20p into the main tread groove. If the outer band of the coin is hidden, the tread is above 3mm. If the band is visible, the tread is approaching the legal limit. (3) Most modern tyres have tread wear indicators — small raised blocks in the tread grooves. When the tread is level with these indicators, the tyre is at 1.6mm.

When should I actually replace tyres — at 3mm or 1.6mm?

Replace at 3mm for safety. The legal limit of 1.6mm is the minimum permitted by law, not the recommended replacement point. In wet conditions, braking distances increase significantly once tread depth falls below 3mm. Tyre manufacturers, road safety organisations, and the motor industry all recommend 3mm as the replacement threshold.

What happens if I get caught with illegal tyre tread?

Each tyre below the legal minimum can result in a £2,500 fine and 3 penalty points. With four illegal tyres, that is a potential £10,000 fine and 12 points — enough for an immediate driving ban. Additionally, illegal tyres can void your car insurance, leaving you personally liable for any accident damage.

Do tyres wear evenly?

Not always. Centre wear suggests over-inflation. Edge wear (both shoulders) indicates under-inflation. One-edge wear (single shoulder) points to misalignment or worn suspension. Patchy or flat-spot wear can result from emergency braking. Uneven wear should be investigated — the underlying cause (alignment, suspension) will often be checked at your MOT.

Is the 20p test accurate enough?

The 20p coin test is a rough guide, not a precision measurement. It gives you a visual indication of roughly 3mm — useful for a quick roadside check. For accurate measurement, use a tread depth gauge. For MOT purposes, testers use calibrated equipment to measure actual depth.

MotR

Tyre Tread · UK Law

Legal Tyre Tread Depth UK

The legal minimum is 1.6mm — but safety organisations recommend replacing at 3mm. Here is how to check accurately, what the different wear patterns mean, and the serious penalties for illegal tyres.

DVSA DataDVLA RecordsFree · No SignupUpdated 2026

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Updated 13 June 2026·5 min read·Reviewed by Ste Robinson, MotR

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Quick Answer

UK legal minimum tyre tread depth: 1.6mm across the central three-quarters of the tread width and around the full circumference. Safety threshold: 3mm (wet stopping distances increase significantly below this). Penalty per illegal tyre: up to £2,500 fine and 3 penalty points. Check depth with a gauge, the 20p coin test, or by looking for built-in tread wear indicators.

Three Ways to Check Tread Depth

Most accurate

Tread depth gauge

Available from motor factors and online for £2–£5. Insert into the main tread groove and read the depth in mm. Measure at multiple points across the tread width and around the tyre.

Quick guide (~3mm)

20p coin test

Insert a 20p coin into the main groove. If the outer band of the coin is hidden by tread, depth is above ~3mm. If the band is visible, get a gauge measurement. Not a legal check — for indication only.

Shows 1.6mm exactly

Wear indicator blocks

Most tyres have small raised blocks moulded into the tread grooves at 1.6mm. When the tread surface is level with these indicators, the tyre is at the legal minimum and must be replaced.

Tread Depth by Vehicle Type

Vehicle type	Minimum tread depth	Where it must be met
Cars, light vans (up to 3.5t), light trailers	1.6mm	Central ¾ of tread width, full circumference
Motorcycle front tyres	1mm	Central ¾ of tread width
Motorcycle rear tyres	1mm	Central ¾ + visible tread on remaining ¼
Mopeds up to 50cc	1mm	Full tread width visible
Agricultural vehicles, motor caravans, etc.	1mm	Full circumference

What Uneven Wear Patterns Tell You

Centre wear

Cause: Over-inflation

Action: Adjust to correct pressure and check for structural damage

Both-edge wear

Cause: Under-inflation

Action: Inflate to correct pressure; inspect sidewalls for damage

Single-edge wear

Cause: Wheel misalignment or worn suspension

Action: Get a wheel alignment check; MOT tester will inspect suspension

Patchy / flat spots

Cause: Hard braking, stuck caliper, or wheel imbalance

Action: Check brakes, balance wheels, inspect for heat damage

Tyre Tread Depth FAQs

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Ste Robinson

Founder, MotR · Last reviewed 13 June 2026

Ste Robinson is the founder of MotR, helping UK drivers check MOT history, tax status, vehicle records and ownership information using official DVLA and DVSA data.

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