Tyre tread depth might seem minor, but it’s one of the biggest safety factors for every driver. From better grip to shorter braking distances, maintaining the right tread depth keeps your car safe and legal. Here are three foolproof ways — including the easy 20p test — to check your tyre tread depth and know exactly when it’s time for new tyres.
There are several parts of car ownership and maintenance that you need to stay on top of all year round, even after your annual MOT and service.
One of these things is tyre tread depth – a small but crucial detail which impacts everything from the performance of your car to how safe it is to drive. Tyre tread depth is so important that it can even leave drivers and car owners with fines, should they allow the tread of their tyres to fall below the legal minimum of 1.6mm.
With that said, and with tyre tread depth such an important part of vehicle maintenance, how can car owners measure and monitor their own tyres?
What is Tyre Tread Depth?
The tread depth of a tyre refers to the measurement from the outside surface to the bottom of the main groove in the tyre.
The legal limit for tyre tread depth is 1.6mm, with anything lower than this considered unsafe and illegal to drive on. This is because without sufficient tyre tread, drivers do not have sufficient control over their vehicle. A worn tyre tread can impact braking distances and reduces friction, which can make steering more difficult – particularly when faced with adverse weather conditions.
Can You Measure Tyre Tread Depth Yourself?
Tyre tread is something that is covered in your annual MOT and service. However, it is also something that vehicle owners should be aware of themselves, using any of the following methods to ensure that their tyre tread does not fall below the legal limit.
1. Tyre Tread Gauge
A tyre tread gauge is a calibrated tool which is placed into a groove on your tyre, measuring the tread depth with a digital or coloured indicator reading.
If using a gauge, it’s recommended that you measure different areas around the full circumference of the tyre to ensure that the tyres are wearing down at a consistent and equal rate. This is also good practice when it comes to checking tyres for bulges or any surface damage.
2. Tyre Tread Marker
Many modern tyres have a tyre tread marker which is printed in the deepest groove of the tyre. Once the surface of the tyre’s rubber is level with the top of this marker, then you know your tyre tread has reached the 1.6mm limit and that tyres need replacing.
This is an easy indicator to keep an eye on.
3. The 20p Trick
The 20p trick involves slotting a 20p coin into the groove of your tyre to see where the rubber sits against the surface of the coin.
If you place the 20p into the groove and are able to see any of the outer border of the coin, then your tyres are worn beyond the legal limit. If the border is concealed by the tyre tread, then you are still within the 1.6mm limit.
