What do the numbers on a tread depth gauge mean?

Most tread depth gauges have markings which indicate the depth in millimetres. These numbers should be used to compare against legal minimums, such as 1.6mm in the UK. They don't tell you how much tread is left on your tyres.

How to measure tyre tread with and without a gauge

Q: How can I measure tyre tread?

There are two methods you can use to measure tyre tread depth: with a gauge and without. Measuring with a gauge is the most accurate method. To do this, you'll need a tread depth gauge, which you can purchase from most automotive retailers or online. Simply press the gauge into the grooves of each tyre and read off the measurement. For maximum accuracy, make sure that the grooves are clean and that you measure in several locations around each tyre. Most gauges have markings which indicate the depth in millimetres. If you don't have access to a gauge, you can use a 20p coin to check whether your tyres are legal/illegal. Place the coin into each groove - if it's visible then there's less than 1.6mm of tread left and therefore replacements will be needed.

Q: How do I use a tread depth gauge?

To use a tread depth gauge, simply press it into the grooves of each tyre and read off the measurement. You can get both digital and analogue devices for this. The digital version will display the measurement on a screen, whereas the analogue version requires you to read the measurement from a small ruler-like scale. For maximum accuracy, make sure that the grooves are clean and that you measure in several locations around each tyre. Once you've taken your readings, compare them against the markings on the gauge for an accurate result.

Finding out the tread depth of your tyres may seem like a daunting task, but there are two methods you can use - with a gauge and without – which make this a quick and easy safety check.

How to Measure with a Gauge

The most accurate way to measure the tread on your tyres is by using a tread depth gauge.

These can easily be purchased from most automotive retailers or online from a number of online sources.

To use one, simply press the gauge into the grooves of each tyre and read off the measurement. You can get both digital and analogue devices for this. The digital version will display the measurement on a screen, whereas the analogue version requires you to read the measurement from a small ruler-like scale.

For maximum accuracy, make sure that the grooves are clean and that you measure in several locations around each tyre.

How to Read a Tread Depth Measure Gauge

Once you’ve taken your readings, you’ll need to interpret them correctly. Most gauges have markings which indicate the depth in millimetres so compare your measurements against these markings for an accurate result.

It’s important to remember that these numbers don't tell you how much tread is left but instead should be used to compare against legal minimums; 1.6mm in the UK for example.

How to Measure Without a Gauge

If you don't have access to a gauge then it's still possible to measure tire tread depth using just a 20p coin! This won’t tell you the level of tread left, but rather whether or not your tyres are legal/illegal.

The outer rim of this coin is 1.6mm thick so place it into each groove - if it's visible then there's less than 1.6mm of tread left and therefore replacements will be needed. This method isn't as precise as measuring with a gauge, it may be helpful in an emergency situation before new tyres can be purchased or if no gauge is available.

Checking tyre wear regularly is essential for safe driving conditions - make sure yours are checked frequently and enjoy reliable journeys ahead!