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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.


Checking your tyres - why do a tyre check?

We all know that when you buy a car you should always kick the tyres. But have you ever wondered why?

Your tyres are one of the most important safety devices on your car. They're the 4 points of contact that keep you gripping the road. Making sure they're in good condition is one of the most important things you can do.

But only 1 in 6 drivers check their tyres before setting off on a long journey.

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

The 3 main tyre checks are:

  • Tyre condition
  • Tyre pressure check
  • Tyre tread depth check

Regular checks on your tyres could save you trouble further down the line.

For example, driving on under or over-inflated tyres can 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.


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 tread depth should ideally be at least 3mm.
  • All tyres should be inflated to the manufacturer's recommended tyre pressure.

The recommended tyre pressure for your car can change depending on how much weight you're carrying. If your car is 'fully-loaded' - when you're going on holiday for example - then you probably want to increase the tyre pressure a bit.


What happens if my tyres aren't legal?

If you’re caught driving on illegal tyres, you could be hit with a fine of £2,500 for each tyre and get 3 points on your licence.

So, if you had 4 illegal tyres, you could face a £10,000 fine and be disqualified from driving, even if you previously had no points on your licence. More importantly, you risk your safety and the safety of others, both in your car and other road users.

If that’s not enough, you might also find any car insurance claim is invalidated if you have an accident while driving on illegal tyres.


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.

Keeping your tyres in good condition 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.


How do I check 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.

Where can I find the recommended tyre pressure for my car?

You should find the recommended tyre pressure for your car either inside the driver’s door or inside the petrol cap.

If not, check your owner’s manual or have a look online.

The recommended car tyre pressure is different for each car – there’s no one-size-fits-all figure. There might also be different recommended tyre pressures depending on the season and the car’s load.

Checking your tyre pressure: step-by-step

  • Unscrew the valve cap on the tyre
  • 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
  • Repeat on your other 3 tyres

Check the tyre pressure all around the car (including your spare tyre if its not a space-saver tyre) 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.


Can I drive with the tyre pressure warning light on?

If you see your tyre pressure warning light appear you should pull over as soon as its safe. Check all 4 tyres for a puncture and see if any of them look under-inflated. A slow-puncture or underinflated tyre means that you have less grip and less control of the car. It's vital to check and fix any problem before it becomes dangerous.


Is tyre pressure different for electric vehicles?

Electric vehicles tend to weigh more because they have heavy batteries. To carry the extra weight, they tend to have higher tyre pressures than petrol and diesel cars. But each car is different and you should follow the manufacturer's guidelines for your specific model.

Electric cars still need to use the correct tyre pressure - using the wrong tyre pressures can have a negative effect on your car's range, on top of the other safety concerns.


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

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 tread depth, the better the grip you have on the road. New tyres typically start off with an 8mm tread depth.

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.

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.


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 3 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.