How often should you check tyre pressure?
Tyre maintenance is easy to ignore while the tyres look fine. Left unchecked, though, small problems become big ones. Here is how often to check pressure, and exactly how to do it.
Know the risks
Under- and over-inflated tyres both compromise handling, braking and grip, and wear faster, so you replace them more often. Higher pressures make the ride harsher, but going below the recommended level is not worth the risk. Correct pressure also improves fuel economy.
- Over-inflated
- A greater risk of a blowout from overheating, wear on the centre of the tread, a reduced contact patch with the road, and longer stopping distances.
- Under-inflated
- A greater risk of aquaplaning, less contact with the road and so less traction, longer stopping distances, wear on the edges of the tread, and higher fuel use.
Check at least monthly. Every two weeks is better.
How often?
As a minimum, check monthly and top up as needed. Checking every two weeks is better. Always check before and after a long journey. Pressures can shift with temperature, but tyres inflated to the manufacturer’s figures should last the distance.
Pressures in your handbook are for cold tyres. Driving heats them and raises the pressure inside, so check before you set off, or after a short trip of under 2 miles. If the tyres are warm, wait for them to cool, up to two hours, before you check.
What you need
- The correct pressures for your vehicle (handbook, or the sticker on the door sill)
- A pressure gauge and a tyre inflator or air pump. Most garages have one, but it is worth keeping a gauge and a pump in the car
- A screwdriver, in case you need to let air out
- A pen and paper, or the notes app on your phone
- A tyre tread gauge and a 20p coin
If you cannot find the figures, contact the vehicle manufacturer with the make, model, registration and tyre size.
How to check and set pressure
Check the units
Pressure is measured in PSI or bar (1 bar is about 14.5 PSI). Use the same units for every tyre.
Measure
Remove the valve cap and press the gauge firmly on the valve until the hissing stops and it gives a reading. Note it, and repeat on each tyre, including the spare.
Inflate if low
Press the inflator hose onto the valve and fill until the gauge shows the right figure.
Let air out if high
Press the metal pin in the middle of the valve with a screwdriver to release air, then check again.
Refit the caps
They keep dirt out of the valve.
Check the tread while you are there
The legal minimum is 1.6 mm. A tread gauge gives an accurate reading, or use a 20p coin: if you can see the coin’s outer band, the tyre may need replacing. Even where the middle of the tread is legal, signs of heavy or uneven wear can mean a fine.
Look for nails or glass, bulges in the sidewall, which show internal damage, and cuts. Any of these means the tyre needs replacing. See when to change tyres.
Prefer us to do it? We offer a tyre pressure check and safety inspection. See our services, or read our tyre pressure guide.