How to check your car's tyres: pressures and tread depth explained

Tyres are unquestionably the most important safety feature fitted to your car — and they're often one of the most overlooked. The only component that’s in contact with the road, tyres play a vital role in helping you maintain control of your car, and can help to save you money in the long run.

Indeed, exclusive research from What Car? found that driving with under-inflated tyres could cost motorists as much as £450 extra per year in increased fuel consumption — as well as substantially increasing stopping distances.

Dangers of not checking tyres:

- Skidding
- Poor handling
- Longer braking distances
- Higher fuel consumption
- Increased tyre wear
- High-speed blowouts

To stay safe and save money, it’s vital that you fully inspect your tyres frequently or before long journeys. Here, we’ll explain how to check your tyres and share simple measures you can take to keep them in tip-top condition.

Of course, if they're damaged or worn, they'll need to be replaced. Here you can read about the best tyres on sale today.

How to check your tyre pressures

Tyre pressure, or the amount of air inside each tyre, is vital to get correct. If there isn’t enough air, too much of the tyre’s surface will come into contact with the road – resulting in increased wear, worse fuel economy and handling issues. Put too much air in the tyres, however, and you’re at a higher risk of skidding, reduced stability and more damage from cracks and potholes in the road. On high-speed journeys in which the air inside the tyres will heat up, there’s also the potential of a blowout.

The Highway Code says you should check your tyre pressures weekly, before a journey to ensure the tyres are cold — taking measurements after a journey could mean your tyres are warmer, leading the air to expand and giving an incorrect reading.

Fortunately, it’s incredibly easy to check your car’s tyre pressures. You can do this at home using a tyre pressure gauge. Our favourite is from Draper, costing around £12, but you can find the best tyre pressure gauges in our product test. Tyre inflators also have gauges, and the Ring RTC4000 is our current pick of the bunch. Alternatively, most petrol station forecourts will have one, or you can speak to your local tyre fitter.

To check a tyre’s pressure level, simply remove the dust cap and press the gauge’s tip onto the valve to take a reading. It's vital the result matches the figure recommended by the manufacturer, which can be found in the car’s handbook or on a sticker, usually located behind the fuel filler flap or in one of the front door jambs. If it doesn't, safety and economy will be compromised.

Remember that pressures may vary depending on wheel and tyre size, and according to how many passengers you’re carrying. Pressure levels can also vary between the front and rear sets of tyres.

How to inflate a tyre

To pump up a tyre, you’ll need a tyre inflator or pump. Again, you can visit a petrol station or ask a tyre fitter to do this, but it's a good idea to buy your own to ensure you don’t get caught short. Our favourite is the Ring RTC4000, but you can find the best tyre inflators in our product test.

Remove each tyre’s dust cap in turn and press the pump nozzle onto the tyre valve. Most inflators will require you to flip down a plastic lever to ensure the pump has an air-tight seal on the valve.

Each inflator works slightly differently, so read the instructions. But in general terms you’ll need to select the correct tyre pressure and push the start button. Most will shut down once the correct pressure is reached. Once you’re done, remove the inflator’s nozzle, replace the dust cap and move to the next tyre.

How to check car tyre tread depth

As well as making sure the car has plenty of grip on all surfaces, the grooves in your tyres are also designed to sweep away water on rainy roads. If your tyres don’t have enough tread, you’ll put yourself and others at serious risk of aquaplaning – in which water forms a barrier between the tyres and the road, resulting in a loss of control.

The minimum legal tread depth is 1.6mm, but 3.0mm or more is strongly recommended by experts. You can use a tread depth gauge to take a reading. Alternatively, the outer rim of a 20p coin happens to measure 1.6mm – pop the coin into the tread and if you can see any of the coin’s rim, replace your tyres immediately. 

You should have at least 1.6mm of tread all round the tyre. While you’re there, look for slices, lumps or gouges on the sides and the tread of the tyre – any damage should be properly inspected, and the tyre replaced if necessary.

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