How to Check Your Tyre Tread Depth

Tyre treads are designed to give good grip on wet roads but this generally decreases as a tyre’s tread pattern wears down or as the depth of water increases. Drivers should take this into consideration and reduce their speed accordingly in wet conditions.


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

Without adequate tread depth your tyres may not be able to perform properly in wet conditions, reducing your safety on the road. It is therefore advisable to consider replacing your tyres well before they reach the legal minimum. Furthermore, drivers whose tyres fail to comply with the minimum tread depth requirements risk a fine of up to £2,500 and three penalty points for each illegal tyre


In situations when your tyres have insufficient tread depth to clear the water properly from the road surface, you may experience the particularly hazardous phenomenon of aquaplaning. During aquaplaning, your tyres lose contact with the road surface and travel on top of the water’s surface. With no contact with the road, you are unable to accelerate, brake or steer effectively, greatly increasing your risk of being involved in an accident. To reduce your risk of aquaplaning, check your tyre tread depth regularly. Take a look at how aquaplaning can affect your safety.

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 tread and round its entire circumference.

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 happens if I need to use my spare tyre?

Temporary use spare tyres are frequently of a different size to the standard road tyres and operating restrictions apply. Failure to observe the advice given in the vehicle handbook and/or on the spare wheel or tyre sidewall could have very serious consequences. Do not exceed the recommended maximum speed when using a temporary use spare tyre and observe the minimum inflation pressure.

My car doesn’t have a spare tyre, what happens if I get a puncture?

Many cars are now equipped with a temporary puncture repair kit rather than a spare tyre. See owner’s handbook on how to use and remember this is only a temporary and not permanent puncture repair.

Do tyre valves need to be replaced?

Valves should be replaced or serviced when renewing tubeless tyres. When checking or adjusting inflation pressure, always ensure the valve is not leaking. A new cap of the sealing type should be fitted.

Can my car tyre be repaired?

Repairs to car tyres must only be carried out by a tyre specialist and in accordance with the current British Standard AU159. Permanent repairs can only be carried out following removal of the tyre from the wheel to allow a thorough inspection internally as well as externally to ensure there is no hidden damage which could result in a catastrophic failure.

Can I repair my tyre myself with a liquid sealant or a plug?

No. Neither externally applied plug repairs, nor liquid sealants can be considered to be a permanent repair. Tyre manufacturers cannot be held responsible for problems resulting from their use. For repairs to self-supporting run flat tyres, consult the relevant tyre manufacturer.

What if there is damage to my wheel?

It is essential that rim and tyre sizes are matched in accordance with the tyre manufacturer’s recommendations and that the assembly is an approved fitment for the vehicle concerned.

The rims on my car are modified, what does this mean for my tyres?

Tyres should not be used on damaged, distorted or modified rims.  This could result in tyre damage, deflation and possible loss of control of the vehicle.

Who should I use to fit and/or repair my tyres?

Tyre fitting and repair should only be entrusted to a trained tyre specialist who has the necessary equipment and expertise. Inexpert fitting can result in operator injury and damage to tyres and rims. Wheels should be balanced after tyres are fitted or replaced.

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