How to Check Your Tyre Tread Depth

Tyre treads are designed to keep the tyre in contact with the road in wet weather. Typically, the deeper the tyre tread, the more water a tyre can clear from the road surface helping to maintain a good grip. As such, as a tyre’s tread pattern wears down or as the depth of water increases less grip is provided. Drivers should take this into consideration and reduce their speed accordingly in wet conditions.

It is important to regularly check the tread depth of your car tyres to ensure that they’re well above the legal minimum. Driving with tyres below this limit is not only a safety hazard but also puts you at risk of incurring a fine of £2,500 and three penalty points per tyre. Ideally, you should check your car tyres every month.

Legal minimum tread depth

The legal minimum tread depth for cars in the UK is 1.6mm, however, you should not risk waiting to replace them until the last minute as a significant amount of tread can be worn in just one emergency manoeuvre. It is advisable to have your tyre replaced once it reaches 2mm however most experts recommend replacing your tyres when they have a minimum of 3mm tread depth. Your car tyre tread should meet the minimum legal tread depth across three quarters of the centre of the tyre around its complete circumference.

Without adequate tyre tread depth, your tyres may not be able to perform properly in wet conditions, reducing your safety on the road. In wet weather, tyre tread grooves help to remove water from the contact patch between your tyres and the road surface meaning your car can brake, steer and accelerate properly. Failing to have the legal depth of tyre tread for a car or other vehicle puts you at a huge risk of accidents. In tests carried out by MIRA, the difference in wet braking distances for cars with 3mm of tyre tread and 1.6mm of tyre tread increased by up to 44%. It is therefore advisable to consider replacing your tyres well before they reach the legal tyre tread limit.

Aquaplaning

When driving on roads with significant standing water, vehicles can be vulnerable to ‘aquaplaning’. Aquaplaning occurs when the water cannot be removed from between the tyre and the road. This causes the vehicle to lose all contact with the road, which effectively leaves the vehicle out of control. The risk of aquaplaning increases as a tyre’s tread depth is reduced as there is insufficient tread to clear the water properly from the road surface.

Lack of contact with the road means you are unable to accelerate or steer effectively, greatly increasing your risk of being involved in an accident. It is also unsafe to try to brake when aquaplaning as contact with the road may be regained in an unpredictable manner, causing the vehicle to spin uncontrollably. To reduce your risk of aquaplaning, check your tyre tread depth regularly.

Tyre tread FAQs

Read the answers to commonly asked FAQs including how to check tyre tread and the impact of wet conditions on roads.

What is the legal minimum tread depth in the UK?

The legal minimum tread depth in the UK is 1.6mm across a continuous band comprising the central three-quarters of the breadth of the tread and its entire circumference.

How can I check my car tyre tread depth?

The easiest way to check that your car tyre tread is above the minimum legal standard is to insert a 20p into the tread grooves on the tyre. If you can’t see the coin’s outer band, your tyres are above the legal limit.

You can also use a tyre tread gauge, which are designed to measure individual tyre grooves.

How do wet conditions or roads affect tyre grip?

Tyre treads are designed to give good grip on wet roads but in general wet grip decreases as the tyre tread depth approaches the legal minimum. Motorists should take this into consideration and reduce speed when driving in wet conditions. For the same reason, motorists may wish to consider replacing tyres before the tread depth reaches the legal minimum.

What is the tread depth of a new tyre?

New tyres have a tread depth of between 8-9 mm.

How long will 3mm tyre tread last?

Generally, tyres with 3mm of tread depth will last between 10,000 and 20,000 miles taking into account different road conditions. However, it is recommended that tyres with 3mm tread depth are replaced as quickly as possible.

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