You have no doubt noticed that your tyres deflate slightly with use. This is perfectly normal, tyres are not entirely airtight and naturally let out some air so you need to check the pressure regularly. Correct pressure is not only vital to ensure your safety on the road, but also to avoid the premature wearing of your tyres and to improve their energy efficiency. Indeed, most tyre damage is the result of incorrect pressure. Find out how to properly manage your tyre pressures, when to put air into your tyres and how much to inflate each tyre.
Incorrectly inflated tyres: what are the dangers?
Incorrect tyre pressure puts you at risk and costs you money due to:
- more rapid wear to your tyres
- longer braking distances
- diminished road holding and driving precision
- increased risk of aquaplaning
- higher fuel consumption
In particular, if your tyres are over-inflated (excess pressure), they will be too rounded reducing the contact surface with the road, which in turn reduces their grip and their ability to absorb irregularities on the road surface. In this case, the tyre will wear more quickly towards the centre of the tyre.
Conversely, under-inflated tyres (insufficient pressure) will have more contact across the breadth of the tyre leading to overheating which can cause a blowout and cause you to lose control of your vehicle. Even before the tyre blows, your vehicle's road holding will be affected, particularly on the wet, and its fuel consumption increased.
What pressure for your tyres?
You can find the recommended tyre pressure for your vehicle in the handbook and/or on a label stuck on the inside of the driver's door or on the petrol cap.
The recommended tyre pressure is not necessarily the same for the front and rear tyres. It is important however to make sure that both tyres on the same axle are inflated to the same pressure.
In some cases you should slightly increase your tyre pressures:
- If you are towing a trailer or a caravan, increase the pressure of your rear tyres by 7 to 12 PSI (0.5 to 0.8 bars).
- In the winter, add 3 PSI (0.2 bars) to the recommended pressure in order to compensate for the reduction in pressure in the cold.
When should you check your tyre pressure?
Remember to check your tyre pressure at least once a month and before you go on any long journeys. You can do this at any petrol station with an air pressure gauge or at home if you have the right equipment (tyre pressure gauge, compressor or foot pump).
If you see any signs of abnormal wear on your tyres or detect any vibrations when driving it is likely that your tyres are incorrectly inflated: in this case check the pressure more often.
Remember to check the pressure of your spare tyre!
How to correctly inflate your tyres
Tyre pressure should always be checked cold i.e. before you have driven more than 3 km (at low speed) or at least 2 hours after driving the car. If you have to inflate warm tyres, add 4 PSI (0.3 bars) to the recommended pressure. Whatever you do, avoid measuring tyre pressure in direct sunlight or when your vehicle has been parked up in hot weather.
To check the pressure, unscrew the cap covering the tyre valve, fit the nozzle of the pressure pump onto the valve and check the reading on the screen. You can then adjust tyre pressure using the + and - buttons.
Don't forget to put the valve caps back on properly to keep the tyres fully airtight.
Never deflate a warm tyre: it is normal for the pressure reading to be high given the temperature. Wait for it to cool down to check the pressure properly.