UK Tyre Tread Depth Law: What is the Legal Limit for Tyres and How to Check It?

Checking your legal tyre tread depth is one of the most critical safety checks you can do on your car. Your tyres are the only contact area between your car and the road, and if your tyres are worn below the legal UK tyre tread depth, your safety may be at risk. Driving on bald tyres affects grip, braking, and handling, as well as incurring a significant risk of severe penalties. In the UK, you can face a £2,500.00 fine and three penalty points per tyre; therefore, if all tyres are illegal, you could be fined £10,000.00, lose your license and go to court.

In this blog, we will bring you up to speed on UK tyre tread laws, covering everything you need to know, from the tread depth on new tyres to the minimum tread depth required, how to check tyre tread, and what will happen if you drive with illegal and dangerous tyres.

What is the Tread Depth of a New Tyre?

A brand-new tyre typically has a tread depth of 8-9mm, giving maximum grip, safer handling, and better water displacement on wet roads. As you drive, the depth of tread gradually wears down, and once it reaches the UK legal tyre tread depth of 1.6mm, the tyre becomes unsafe and illegal. Experts recommend replacing tyres at around 3mm to maintain braking performance and avoid longer stopping distances. Regular tyre tread checks help you track wear and stay within the UK tyre legal limit.

What is the Legal Tyre Tread Depth Limit in the UK?

The UK legal tyre tread depth is 1.6mm across the central three-quarters of the tyre and its full circumference. Driving on tyres with tread depths below the minimum in the UK is illegal, unsafe, and one of the most common reasons for failing an MOT. Bald or worn tyres reduce grip, increase stopping distances, and put you at greater risk in the wet.

To stay safe and avoid fines, make it a habit to check your tyre tread depth at regular intervals yourself using the 20p test, or arrange for an inspection at your local garage or with a mobile mechanic if you are unsure.

How to Check Car Tire Tread Depth?

To ensure your tyres are legal and safe in the UK, the tread depth must be at least 1.6mm. This legal limit must not only be over 1.6mm, but the minimum tread depth must be maintained on the tread across the entire circumference of the tyre and the central three-quarters of the tread surface. It is illegal and unsafe to drive with tread depth below 1.6mm, which may result in a fine or an MOT failure.

If you are unsure that your tyres meet the UK legal minimum tyre tread depth, there are three quick and easy checks:

1. The 20p Test

The 20p Test is a quick and easy method to check whether your tyres meet the legal minimum tyre tread depth in the UK.

• Place the 20p in the primary tread grooves.
• If the outer rim of the coin is hidden, your tyres are safe and meet the minimum tread depth requirement.
• If you can see the outer rim of the coin, your tyre may be at or below the legal limit; you should consult with a trained professional.

We recommend you do this check every couple of weeks and before long journeys.

2. Checking tyre tread with tyre tread wear indicators

Most tyres come fitted with built-in tread wear indicators, which are small, raised bars located in the grooves of the tyre.

If the tread surface is level with the indicators, the tyre has reached the minimum tread depth and should be changed immediately.

3. Checking tyre tread with a tyre tread depth gauge

For the most accurate reading, you can purchase a tyre tread depth gauge. Insert the gauge into the tread grooves, and it should display the current tread depth in millimetres.

These are sold in both analogue and digital forms, allowing you to regularly check your tyre tread and ensure your tyres are safe and compliant with UK tread depth regulations.

What Happens If you have an Accident with Illegal or Bald Tyres?

Driving with tyres worn below the UK's legal tyre tread depth is not only unsafe, but it also carries serious legal and financial risks. If you're involved in an accident and your tyres are found to be under the minimum tread depth in the UK, the consequences can be severe.

Here's what can happen if you drive on illegal or bald tyres:

• Insurance invalidation: Your insurer may refuse to cover you if your tyres are below the legal tread depth in the UK, leaving you to pay for all damages.
• Heavy fines and penalty points: You could face a fine of up to £2,500 per tyre and three penalty points on your license. Four illegal tyres could cost you £10,000 and 12 penalty points, risking a driving ban.
• Increased accident risk: Bald tyres have poor grip, longer braking distances, and a higher chance of aquaplaning, especially in wet conditions.
• MOT failure: Worn tyres below the tyre tread minimum depth will cause your car to fail its MOT, meaning it's not legally roadworthy.
• Legal consequences: If your bald tyres contribute to an accident, you could face prosecution for dangerous driving.

FAQs

1. Is 3mm tyre tread legal?

Yes, a 3mm tyre tread is legal in the UK. The minimum legal tyre tread depth in the UK is 1.6mm, so 3mm is above the legal limit. In fact, experts recommend replacing tyres when the tread depth is around 3mm to maintain optimum grip, braking performance, and safety.

2. Is 2mm tyre tread ok?

A 2mm tyre tread is technically above the legal limit of 1.6mm, so it is still legal. However, tyres with a 2mm tread are considered close to the minimum tread depth, and their performance in wet conditions is significantly reduced. It’s advisable to plan a replacement soon.

3. What is the minimum tyre tread depth allowed by law?

The minimum tyre tread depth in the UK is 1.6mm across the central three-quarters of the tyre, around its full circumference. Driving below this legal tyre tread depth is illegal and unsafe.

4. What is the legal limit for tyres to pass MOT?

To pass an MOT, car tyres must meet the UK legal tyre tread depth, which is 1.6mm across the middle three-quarters of the tread. Bald or worn tyres below this limit will result in a failed MOT.

5. How long does the average tyre last?

The lifespan of a tyre depends on driving style, road conditions, and maintenance, but on average, car tyres last around 3-6 years or 25,000-50,000 miles. Regular tyre tread checks help you monitor wear and plan timely replacements.

6. What is the lowest legal limit for tyre tread?

The lowest legal tyre tread depth in the UK is 1.6mm. Tyres worn below the UK tyre legal limit are illegal, unsafe, and could lead to fines, MOT failure, or insurance issues in the event of an accident.

7. How long does it take for the tyre tread to wear down?

Tyre tread wear varies depending on factors like driving habits, road conditions, and maintenance. On average, tyres wear down from 8-9mm on new tyres to the 1.6mm legal limit over 3-6 years or 25,000-50,000 miles. Regular tyre tread checks ensure you replace them before reaching the minimum tread depth in the UK.

Conclusion

Keeping an eye on your tyre tread depth is one of the easiest and most important steps to staying safe and compliant with UK road regulations. The UK legal tyre tread depth is 1.6mm but replacing your tyres with around 3mm is strongly recommended to maintain grip, reduce stopping distances, and avoid accidents. Regular tyre tread checks, whether with the 20p test, wear indicators, or a depth gauge, will ensure you never risk fines, MOT failures, or unsafe driving conditions.

Tyres are just one part of vehicle safety. Unexpected breakdowns or repairs can still occur, which is where Warranty Direct comes in. With cover for repairs, parts, and labour, Warranty Direct helps protect you against costly repairs, so you can focus on driving safely with the confidence that your vehicle is looked after.

Stay safe, stay legal, and consider pairing regular tyre tread checks with the added security of Warranty Direct extended car warranty cover for complete protection on the road.