tyre showing tread wear indicators

How to check tyres

Tyres are the only part of a vehicle that comes into contact with the road surface. Having tyres that are in good condition with adequate tread depth is vital when it comes to safe grip and vehicle handling. The tread on your tyres is what allows your vehicle to grip the road surface. Tyre manufacturers focus on designing tread patterns that maximise road grip and improve vehicle handling. Tyre tread patterns vary from asymmetrical to directional designs but they all have a common purpose which is to provide traction and disperse water from the road surface.

If your tyres are very low on tread they lose their effectiveness & may even be illegal, which could not only invalidate your insurance but land you with a hefty fine. An illegal tyre could lead to a £2500 fine and 3 points on your license; if all four of your tyres are illegal you could end up losing your license and paying a £10,000 penalty!

Here, we are going to explain how to check your tyres to make sure you, and your passengers, remain safe on the road.

What does tyre tread depth mean?

Tread depth is the vertical measurement in mm of the grooves of a tyre. A new tyre is supplied with around 7-8mm of tread. As you drive the “tread” of the tyre gradually wears away; it’s not until a tyre has only 1.6mm of tread that you legally need to replace it. Most tyre safety experts recommend tyres are replaced at around 3mm.

How tyre tread depth impacts stopping distance

As a general rule, the less tread you have on your tyres the longer your stopping distance will be. This is more apparent in wet conditions when driving with low tread is particularly hazardous.   This is because as the tread of the tyre gets shallower it loses it’s ability to disperse surface water quickly enough which causes a build up of water between the tyre and the road surface. This leads to a loss of grip, control and potentially even aquaplaning.

MIRA, the UK’s automotive research organisation have found that stopping distances increase dramatically when tyre tread has worn down to 3mm.

Tyre stopping distance chart

How to check your tyres

There are three main ways to check your tyre tread depth.

  • Using a tread depth gauge
  • Using the tread wear indicators
  • Using a 20p coin

How much tread you need on tyres

Make sure your tyres are safe & legal by knowing what tread depth is required.

  • 8mm: New tyre
  • 3mm: Tyre change recommended
  • 1.6mm: Legal limit. Tyre is 100% worn

You must have at least 1.6mm across the central 3/4 of the tread for your tyre to be legal.

Tread depth gauge

A tread depth gauge is designed specifically for measuring tyre tread and will give very accurate readings. You can buy these online or simply call into any of our branches for one of our technicians to carry out a free tyre safety check.

tyre showing tread wear indicators

Tread wear indicators

Tread wear indicators are built into the tread of your tyres to help you assess the tread depth. When you tyre tread has worn down level to the indicators (the square bumps between the tread) you’ll know your tyres have reached the legal limit and need replacing.

20p tyre check

20p coin tyre check

If you’d like to carry out a tyre check at home then the easiest way to do this is with a 20p piece. Simply insert the coin into the grooves of your tyre; if you can see the outer band of the coin your tread is low and your tyre may need replacing.

Are my tyres legal?

For your tyres to be legal they must have:

  • A minimum of 1.6mm across the central 3/4 of the tyre tread
  • Have no ply or cords exposed
  • Have no sidewall damage such as bulges, rips or cuts
  • Be correctly inflated

Each illegal tyre has a maximum penalty of £2500 and 3 points. If all your tyres are illegal you could find yourself with a £10,000 fine and losing your license.

How often should I check my tyres?

Getting into the habit of checking your tyres regularly is essential for safe driving. 

  • Check your tyres at least once a month
  • Check tread depth is over 3mm
  • Don’t forget to check the inside edge of your tyres. You can do this by putting your steering wheel onto full lock.
  • Check tyre pressures at least once a month
  • Carry out additional checks before any long journey

If you’d like any further advice on checking your tyres please contact your local Eden Tyres & Servicing branch or book a free tyre safety check online.