What Is the Minimum Legal Tyre Tread Depth in the UK?
Under the Road Vehicles (Construction and Use) Regulations 1986, UK law requires a minimum tread depth of 1.6mm across the central three-quarters of the tyre's width, around its entire circumference. This applies to cars, light vans, and trailers up to 3,500kg.
While 1.6mm is the legal minimum, tyre safety charity TyreSafe recommends replacing tyres at 3mm. Their research shows that in wet conditions, stopping distances at 1.6mm can be 44% longer than at 3mm — the difference between a near-miss and a serious collision.
What Are the Penalties for Driving on Illegal Tyres?
Illegal tyres carry some of the steepest roadside penalties of any motoring offence:
- A fine of up to £2,500 per tyre
- 3 penalty points per tyre on your driving licence
- An automatic MOT failure
- Potential insurance invalidation in the event of an accident
With four illegal tyres you could face up to £10,000 in fines and 12 penalty points — enough to trigger an automatic six-month driving ban.
How to Check Your Tyre Tread Depth
1. Tread Depth Gauge
The most accurate method costs under £5 from any motor factors. Push the probe into the main tread groove and read the millimetre measurement directly.
2. The 20p Coin Test
Insert a 20p coin into the main tread groove. If you can see the outer band of the coin (around 2.8mm wide), your tyres are approaching the legal limit. This is a useful quick check but not a substitute for a gauge.
3. Tread Wear Indicators (TWIs)
All modern tyres have moulded TWIs — small raised blocks at the base of the tread grooves. A triangle or "TWI" marking on the sidewall shows you where to look. When the tyre tread wears flush with these indicators, you have reached 1.6mm and must replace the tyre immediately.
Do Worn Tyres Fail an MOT?
Yes — tyre condition is one of the most common causes of MOT failures. Testers inspect:
- Tread depth across the central three-quarters of each tyre
- Sidewall condition — cuts, bulges, or exposed cords
- Correct size and speed rating for the vehicle
- Matching tyre types on the same axle
A tyre below the legal limit is a Dangerous fault — the car cannot be driven away from the test centre until it is replaced.
How Long Do Tyres Last?
Lifespan varies considerably depending on:
- Driving style — hard acceleration, heavy braking, and fast cornering accelerate wear
- Vehicle type — heavier cars and performance vehicles go through tyres faster
- Wheel alignment — misaligned wheels cause uneven, premature wear
- Tyre quality — premium brands (Michelin, Continental, Bridgestone) typically outlast budget alternatives
As a guide, front tyres on a front-wheel-drive car typically last 20,000–30,000 miles. Rear tyres last considerably longer as they carry no steering load.
Tyre Replacement Costs in the UK (2026)
- Budget (13–15 inch): £40–£70 fitted
- Mid-range (16–17 inch): £70–£120 fitted
- Premium (17–19 inch): £100–£250+ fitted
Most tyre centres include fitting and balancing. Independent garages may charge £10–£20 per tyre separately. Always get at least three quotes — prices between local garages and national chains vary significantly.
Quick Tyre Safety Checklist
- Check tread depth at least once a month and before long journeys
- Check tyre pressure cold (before driving more than 2 miles)
- Inspect sidewalls for damage after hitting a kerb or pothole
- Never mix radial and cross-ply tyres on the same vehicle
- When replacing just two tyres, fit the new ones on the rear axle