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How do you check tyre pressure and tread depth?

One in five breakdowns are caused by worn or incorrectly inflated tyres. According to Highways England, only one in six drivers check their tyres before setting off on a long journey.  Here's how you check your tyre pressure and tread depth.

A close up of a driver checking their tyre tread depth 

Carrying out regular tyre checks and making sure they’re in good condition before a journey is essential. This includes tyre pressure and tyre tread depth.

Regular maintenance on your tyres could save you trouble further down the line. For example, driving on under or over-inflated tyres could lead to problems with your braking, tracking, fuel-efficiency and suspension.

Driving on poorly maintained tyres could also cost you more money - increasing your fuel consumption and increasing the strain on other parts of your car.

But worryingly, only one in six drivers check their tyres before setting off on a long journey. Here’s how you check the condition, pressure and tread depth of your tyres.


What are the tyre laws in the UK?

Your tyres are pivotal to your car’s safety and that means there are strict laws dictating how you maintain them: Tyres must be the right type and size for your car

The minimum tyre tread depth for the UK is 1.6mm, but try not to let them fall below 3mm

All tyres should be inflated to the manufacturer's recommended tyre pressure.

If you’re caught driving on illegal tyres, you could be hit with a fine of £2,500 for each tyre and get three points on your licence.

So, if you have four illegal tyres, you could face a £10,000 fine and be disqualified from driving, even if you previously had no points on your licence. On top of all this, you risk your safety and the safety of others. If that’s not enough, you might also find any car insurance claim is invalidated if you have an accident driving on illegal tyres.

Keeping your tyres in good nick should be part of your regular car maintenance routine. You should also understand the various labels, markings and ratings on your tyres.

And, if any of them aren't up to scratch, you might need to change your tyres.

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How do I check the condition of my tyres?

It’s easy to check the condition of your tyres with a visual inspection.

Take a good look around each of the tyres and make sure that there aren’t any cuts, tears or bulges on any of them. Check for stones and nails in the tyres, as well as any damage to the side wall.

It’s good practice to do this once a month, but also whenever you’ve bumped your tyres on the kerb, or potentially damaged them in any other way.


How do I check my tyre pressure?

It’s important to check your tyre pressure when they’re cool, as that’s when you’ll get the most accurate measurement. Ideally, you should check them before you start your journey.

You need to use a pressure gauge to get a measurement. You can buy one to use at home. Alternatively, petrol stations should have one that’s usually free to use.

The recommended tyre pressure is different for each car – there’s no one-size-fits-all figure.

You should find your recommended tyre pressures inside the driver’s door or inside the petrol cap. If not, check your owner’s manual or have a look online.

There might also be different recommended tyre pressures depending on the season and the car’s load.

First, unscrew the valve cap on the tyre and attach the gauge firmly to take a reading. 

If the reading is lower than the recommended pressure, inflate your tyres to match. If it’s higher, let some air out.

When you’ve finished, take off the gauge quickly so no air escapes, and replace the cap. Check the tyre pressure all around the car (including your spare tyre if you have one) and then you’re good to go.


How often should you check your tyre pressure?

There’s no hard and fast rule, but it’s good practice to check your tyre pressure every month. If you make it a regular habit, it should quickly become something you do automatically.


What’s the legal minimum depth of tread for car tyres?

The UK legal minimum tread depth for cars is 1.6mm across the central three-quarters of the width of the tyre, and across the entire circumference.

Your tyre tread is what helps keep you steady on wet roads. The tread channels water into the grooves of the tyre, giving you more control on the road.

The greater your tyre depth, the better the grip you have on the road.

Once the tread starts to wear down, its road grip is  reduced. This increases your braking distance and also the risk of skidding and aquaplaning.

This is why driving on bald tyres could be incredibly dangerous.

Once your tread gets this low, you must replace the affected tyre.

Some manufacturers recommend that you replace your tyres after the tread goes down to about 3mm, as that’s when its performance starts to drop.

New tyres typically start off with an 8mm tread depth.


How do I measure my tyre tread depth?

New tyres should now come with a tread depth indicator.

If you have older or more worn tyres, the  easiest way to measure tread depth is with the 20p tyre test.

Place a 20p coin in the main grooves of the tyre. If you can’t see the outer rim on the coin, then your tread depth is above the legal minimum. However, if that outer rim is still visible your tyre tread depth could be too low. If this happens, it’s important to get them checked by a professional and, if necessary, replaced.

Make sure that you carry out the 20p tyre test in at least  three different places along each tyre, as one part might be more worn than another.


How often should I check my tyre tread depth?

To ensure your tyre tread depth always exceeds the UK legal minimum, consider doing the 20p tyre test at least every month. You should also check your tyres before going on any long journey.