How to Check Your Tyre Tread Depth at Home
Your tyres are the only part of your car that touches the road, yet most drivers in {location} rarely check their tread depth between MOTs. Driving on worn tyres is both dangerous and illegal in the UK. Here's how to check yours in under five minutes.
The Legal Minimum
UK law requires a minimum tread depth of 1.6mm across the central three-quarters of the tyre, around its entire circumference. Driving below this limit is an offence that carries a fine of up to £2,500 and three penalty points per tyre. Four illegal tyres could mean a £10,000 fine and 12 points — an automatic driving ban.
The 20p Test
The simplest way to check tread depth at home is the 20p test:
- Take a 20p coin and insert it into the main tread grooves of your tyre
- If you can see the outer band of the coin, your tread is below 1.6mm and the tyre is illegal
- If the outer band is hidden by the tread, you have sufficient depth
- Check in at least three places across the tyre width and at several points around the circumference
This test gives you a pass/fail answer at the legal limit. However, most tyre professionals and road safety organisations recommend replacing tyres at 3mm. Braking distances increase significantly between 3mm and 1.6mm, especially in wet conditions.
Using a Tread Depth Gauge
For a more precise reading, buy a tread depth gauge from any motor factors or online retailer. They cost £2-£5 and give you an exact millimetre reading. Push the probe into the tread groove and read the measurement. Check multiple points across the width and around the tyre.
Tread Wear Indicators
Every tyre manufactured for the UK market has built-in tread wear indicators (TWIs). These are small raised bars sitting at 1.6mm height inside the main tread grooves. When the tread surface is level with these bars, the tyre has reached its legal limit. Look for small triangle markers or the letters "TWI" on the sidewall — they point to the indicator locations.
What Uneven Wear Tells You
While checking depth, pay attention to the wear pattern:
- Worn on both edges: The tyre has been consistently under-inflated
- Worn in the centre: The tyre has been over-inflated
- Worn on one edge only: The wheel alignment is out — get it checked
- Patchy or cupped wear: May indicate worn suspension components, a wheel balance issue, or both
Uneven wear means you're not getting full life from your tyres and your car may not handle safely. A tyre fitter in {location} can diagnose the cause and correct it when fitting replacements.
How Often to Check
Check your tyre tread depth at least once a month and before any long journey. It takes a few minutes and could save your life. Make it part of your routine — do it when you check your tyre pressures, which should also be monthly.
What to Do If Your Tyres Are Worn
If any tyre is approaching 3mm, start getting quotes from tyre fitters in {location}. Don't wait until it hits 1.6mm — by that point, your wet-weather braking distance has already increased dramatically. Replace tyres in pairs on the same axle where possible for balanced handling.