How to Check Your Tyre Tread Depth at Home

Why Tyre Tread Depth Matters

Tyre tread depth directly affects how quickly your car stops in wet conditions. Tests by TyreSafe have shown that stopping distances in the wet increase by up to 44% when tyres are at the 1.6mm legal minimum compared to 3mm. Checking your tyre tread depth takes under a minute and should be done monthly.

Method 1: The 20p Coin Test

This is the quickest way to check if your tread is above or below the legal 1.6mm limit. Insert a 20 pence coin into the main tread grooves of your tyre. The outer border of a 20p coin is approximately 1.6mm wide. If the border is completely hidden by the tread, you are above the legal minimum. If you can see the border clearly, your tyres are likely at or below the legal limit and should be replaced.

Method 2: Tread Wear Indicators

Most modern tyres have tread wear indicators — small raised sections moulded into the bottom of the main tread grooves. When the surface of the tyre wears down to the level of these indicators, the tyre is at or below 1.6mm. Look for a small triangle or the letters "TWI" on the tyre sidewall to locate the indicator positions.

Method 3: Digital Tread Depth Gauge

For the most accurate reading, a digital tread depth gauge (available from around £5 online) gives you a precise measurement in millimetres. Check the tread at three points across the width — inner, centre and outer — and at multiple points around the circumference, as uneven wear can cause different readings.

When to Call Saltire Mobile Tyres

If any reading is below 3mm, we recommend booking a mobile tyre inspection. Our technicians serve Leeds, Bradford, Wakefield, Huddersfield, Dundee and Aberdeen and can assess your tread depth and arrange same-day replacement if needed.