Tyre Tread Depth UK: Legal Limits & How to Check with a Coin

Key Takeaways

• Adequate tyre tread depth is vital for grip, shorter braking distances, and stability in wet or icy conditions, reducing the risk of aquaplaning.
• UK law requires a minimum tread depth of 1.6mm across the central three-quarters of the tyre for safe and legal driving.
• Illegal tyres can cost you dearly, with fines of up to £2,500 and 3 points per tyre, plus potential insurance issues.
• Use the 20p test—if the coin’s outer rim is visible in the tread, your tyres may be below the legal limit.
• The Ordiniq Digital Tyre Tread Depth Gauge and AutoPump keep your tyres safe, legal, and road-ready at all times.

Why Your Tyre Tread Depth Is Critical for Road Safety

Your tyres are the only part of your car that makes direct contact with the road, and their grip is essential for safe braking, cornering, and handling, especially in wet or icy conditions. Adequate tread depth allows your tyres to channel water away from the contact patch, reducing the risk of aquaplaning. 

When tread depth is too low, water can’t escape quickly enough, causing your car to lose traction. This increases stopping distances and makes steering less responsive, turning even short journeys into potential hazards. Regular checks ensure you spot problems before they put you at risk.

UK Legal Tyre Tread Requirements: Know the Limits

In the UK, the law requires a minimum tread depth of 1.6mm across the central three-quarters of the tyre, all the way around its circumference. This measurement is taken using a calibrated gauge, and anything below this limit is considered illegal. Tyres worn below 1.6mm are far less effective at dispersing water, which can double stopping distances in wet conditions and significantly reduce grip.

Your tyres deserve more than a quick glance, check them properly.

Penalties for Illegal Tyres: Fines & Points

Driving on tyres below the legal limit can lead to a £2,500 fine per tyre and 3 penalty points per tyre on your licence. If all four tyres are illegal, that can reach up to thousands of pounds in fines and 12 points, enough to face an immediate driving ban. 

Police and MOT testers regularly check tread depth, so being below the limit can result in instant penalties and increased accident risk.

The Simple 20p Test: Check Your Tyres in Seconds

One of the quickest and easiest ways to check if your tyres are safe and legal is with a simple coin you probably already have in your pocket.

How to Perform the 20p Coin Test

1. Find a clean section of tread – Wipe away any dirt or debris so you can clearly see the grooves.
2. Insert a 20p coin into the tread groove – Hold it upright so the outer rim of the coin is facing you.
3. Check the rim visibility – If you can see the outer border of the coin, your tread depth is likely below 1.6mm.
4. Repeat across the tyre – Test several points across the width and around the full circumference, as some areas may wear faster than others.
5. Check all four tyres – Don’t forget the spare if your car has one, especially before a long journey.

What the Results Mean for Your Safety

If the rim of the coin is visible, your tread depth is likely under the legal limit. Grip, braking, and water dispersal are reduced, making the tyre unsafe and in need of immediate replacement.

If the rim is hidden, your tread is above 1.6mm and legal, but performance drops well before this point. Keep checking regularly and consider replacing at around 3mm for better safety.

If you can see the coin's rim, your tyres need immediate replacement; if it's hidden, they're legal (image courtesy of TyreSafe). 

Alternative Ways to Check Your Tyre Tread

While the 20p coin test is quick and handy, there are other methods that can give you a clearer or more precise picture of your tyre’s condition.

Using Tyre Tread Wear Indicators

Most modern tyres are fitted with tread wear indicators, small raised bars moulded into the grooves. As the tyre wears down, the tread becomes level with these bars, signalling that the tyre is close to or at the legal limit. These indicators are easy to spot once you know what to look for and offer a quick visual check without any tools.

Digital & Manual Tread Depth Gauges

For a more accurate measurement, you can use a tread depth gauge. Manual versions are inexpensive and simple to use, while digital models like Ordiniq Digital Tyre Tread Depth Gauge provide quick, easy-to-read results. 

Both allow you to check the depth in multiple spots across the tyre, which is important because tread wear is often uneven. Keeping a gauge in your glovebox ensures you can check anytime, especially before a long journey.

Avoid breakdowns by catching tyre issues before they become problems.

Why 1.6mm Isn't Enough: The 3mm Recommendation

The legal minimum of 1.6mm may keep you compliant, but it doesn’t guarantee safety. Many experts recommend replacing tyres at 3mm, as the extra tread provides better grip and control.

Experts say that stopping distances can be over 40% longer when tread drops from 3mm to 1.6mm in wet weather. With less tread, water isn’t cleared effectively, increasing the risk of aquaplaning and making braking less reliable. At motorway speeds, that extra distance can be the difference between avoiding an accident and a dangerous collision.

At 3mm, tyres are still safe for most conditions, but at 1.6mm, grip in the rain is noticeably reduced and stopping distances are at their worst.

Signs It's Time to Replace Your Tyres

Knowing when to change your tyres isn’t just about tread depth—other warning signs can point to trouble.

Cracks or bulges in the sidewall can weaken the tyre’s structure and increase the risk of a blowout. Cuts or sharp objects lodged in the tread can cause slow leaks or sudden punctures. Uneven wear patterns might signal alignment or suspension problems, which can shorten tyre life.

Age also matters. Even if the tread still looks fine, tyres over 5–6 years old can harden, losing flexibility and grip. This can make them less effective in wet conditions and more prone to cracking.

Regular checks help you spot these issues early and replace tyres before they compromise your safety.

Maintaining Your Tyres for Longer Life & Better Safety

A few simple habits can significantly extend tyre life and keep you safer on the road.

1. Correct Tyre Pressure

Underinflated tyres wear out faster, waste fuel, and can overheat, leading to potential blowouts. Regular checks with a reliable tool like the Ordiniq AutoPump can help keep them at the right pressure.

2. Rotation & Alignment

Rotating tyres every 8,000 to 13,000 kilometres ensures even tread wear. Regular wheel alignment checks also prevent premature wear caused by suspension issues.

3. Driving Habits

Smooth braking, gentle cornering, and avoiding potholes where possible all help preserve tread depth and protect your tyre’s structure.

Ordiniq: Check & Inflate Your Tyres Anytime

Your tyres keep you connected to the road, so their condition matters. The Ordiniq Digital Tyre Tread Depth Gauge lets you check wear instantly, while the AutoPump keeps pressure perfect,  your all-in-one kit for safe, smooth driving anywhere.

From pressure checks to perfect inflation, Ordiniq has you covered with the AutoPump (pictured above) and Digital Tyre Gauge.

Ordiniq Digital Tyre Tread Depth Gauge

Worn tyres reduce grip, increase braking distance, and can even lead to dangerous blowouts. The Ordiniq Digital Tyre Tread Depth Gauge removes the guesswork, delivering accurate readings in seconds.

• Clear digital display – easy to read, even in low light.
• Compact, durable design – fits in your glovebox or toolkit.
• Universal fit – works with car, van, and motorcycle tyres.

Whether it’s a daily check or a pre-trip inspection, this gauge helps you drive confidently, knowing your tyres are safe and legal.

 “The digital display on this gauge is crystal clear. Makes checking my tyres before a trip quick and easy. Highly recommend!” – Alan F.

Ordiniq AutoPump

Low tyre pressure can cause uneven wear, poor handling, and reduced fuel efficiency. The Ordiniq AutoPump gives you control over your tyre pressure on the spot — no queues, no faulty petrol station machines.

• 150 PSI cordless power – inflates car, bike, and sports tyres with ease.
• Set & forget – stops automatically at your target PSI.
• Built-in LED torch & SOS light – perfect for night-time emergencies.

Lightweight and portable, it should be in every boot, helping prevent tyre damage and extending tyre life.

“It was easy to order and the machine works really well. So impressed with it I have bought my daughter one as well. Rather than keep going to petrol station and paying money it’s better to have this in the car” – Barbara

Check your tread, top up your tyres, order your Ordiniq Digital Gauge & AutoPump today for safer, smoother journeys.

Frequently Asked Questions (FAQs)

How often should I check my tyre tread?

You should check your tread at least once a month, before any long journeys, and whenever there’s a major change in weather. This ensures your tyres stay safe and effective in all driving conditions.

Is it better to check tyres when they’re hot or cold?

Always check your tyres when they are cold, before driving. Heat from driving can expand the rubber slightly, giving less accurate pressure and tread readings. Cold readings provide the most reliable measurement.

Do new tyres need to be checked?

Yes, even brand-new tyres can develop uneven wear if wheel alignment is off or tyre pressure is incorrect. Early checks ensure they last longer and maintain optimal road grip.

Can tyre tread depth affect fuel efficiency?

Absolutely. Worn or uneven tyre tread increases rolling resistance, which makes your engine work harder. This can lead to higher fuel consumption and extra costs over time.

Is the Ordiniq Digital Tyre Tread Depth Gauge easy to use?

Yes! Simply press the Tyre Tread Depth Gauge against your tyre tread and the digital display instantly shows a clear, accurate reading. No guesswork, no squinting, just quick and reliable results every time.