Your tyres are the only part of the car touching the road, and tread depth is the simplest thing to check yourself. It takes a couple of minutes and can save you a fine as well as a skid.
The UK legal limit
In the UK the legal minimum tread depth for cars is 1.6mm across the central three-quarters of the tyre, around its entire circumference. Driving on tyres below that can lead to a fine of up to £2,500 and three penalty points per tyre.
The 20p coin test
Place a 20p coin into the main grooves of the tyre. If the outer band of the coin is hidden by the tread, your tyre is above the legal minimum at that point. If you can see the whole outer band, it is close to or below the limit. Test several places across the width and around the tyre.
Using a tread depth gauge
A gauge costs only a few pounds and gives an exact reading in millimetres. Push the probe into a groove until the base rests flat on the tread, and read the depth. Take readings on the inner, middle and outer parts of the tyre, since wear is often uneven.
Why replace before 1.6mm
Grip, particularly in the wet, falls off noticeably as the tread wears. Many safety organisations recommend replacing tyres at around 3mm rather than waiting for the legal limit, because braking distances in wet conditions grow significantly.
What uneven wear is telling you
Wear on only one edge can point to alignment problems, while a worn centre often means over-inflation. Either is worth getting checked when you replace the tyres.
Common questions
How often should I check my tread?
Once a month, and before a long journey. It is easiest to check pressures and tread together.
What is the tyre wear indicator?
Small raised bars in the main grooves that sit at 1.6mm. When the tread is level with them, the tyre is at the legal limit.
Do I need to replace all four tyres together?
Not always, but tyres on the same axle should be matched, and on four-wheel-drive cars it is best to keep wear similar on all four. We can advise.
Can you check my tyres at home?
Yes. When we visit to fit or repair tyres, we are happy to check the rest of the set.