How do I check tyre tread depth?

Checking your tyre tread depth

Regular tread depth checks are one of the simplest and most important things you can do to stay safe on the road. There are two easy methods available to every driver.

The 20p test

This is the quickest way to get a rough indication of your tread depth:

1. Take a 20p coin and insert it into the main tread grooves of your tyre
2. If you can see the outer band of the coin above the tread, your tyre may be below or approaching the legal limit
3. If the outer band is hidden by the tread, you have more than 1.6mm remaining

Check in several places across the width of the tyre and around its circumference, as wear can be uneven.

Using a tread depth gauge

For a more precise measurement, use a tread depth gauge. These are inexpensive and available at most motor accessory shops. Place the gauge into the main tread grooves and read the measurement. Check at least three points across the tyre and several points around the circumference.

What depth is safe?

The UK legal minimum for car tyres is 1.6mm across the central three-quarters of the tread. However, many safety organisations recommend replacing tyres at 3mm, because wet braking performance drops significantly below this level.