The 20p Coin Test

The quickest way to check your tyre tread depth is the 20p coin test. Insert a 20p coin into the main tread groove of your tyre. If the outer border of the coin is hidden by the tread, your tyres are above the legal minimum of 1.6mm. If the outer border is clearly visible, your tyres may be at or below the limit and should be inspected or replaced immediately.

For a more accurate reading, use a tyre tread depth gauge — available from any motor factors for a few pounds. Check at multiple points across the tyre width, as tyres often wear unevenly.

Where Are the Tread Wear Indicators?

Modern tyres have tread wear indicators (TWIs) moulded into the base of the main tread grooves. These are small raised bars set at 1.6mm height. When the tread wears down to the level of these indicators, the tyre has reached the legal limit and must be replaced.

Look for the letters "TWI" or a small arrow on the tyre sidewall to locate where the indicators are positioned within the groove.

When Should You Actually Replace Your Tyres?

The legal minimum is 1.6mm, but most tyre safety experts — and many manufacturers — recommend replacing tyres at 3mm. At 3mm, wet braking distances begin to increase significantly. By 1.6mm, a tyre is substantially less safe in wet conditions than a new one.

If your tyres are at or below 3mm, contact Easy Mobile Tyres for a mobile tyre replacement quote. We'll come to you and fit new tyres at your location — no garage trip required.