The tyre pressure needs to be adjusted if you're changing wheels or planning to drive with a different load. It's normal for tyre pressure to decrease over time. Adjusting it so that you have the correct pressure for the current situation helps ensure an even tyre wear and high performance.
The tyres need to be at ambient temperature when the pressure is checked and adjusted. This is referred to as having cold tyres. Never release air from a warm tyre. When it cools down, the internal air pressure drops, which can lead to underinflated or even entirely deflated tyres.
The tyres can warm up very quickly and should be considered warm if driven for longer than approximately 1.5 km (1 mile). They often need about 3 hours of cooling down before reaching ambient temperature again.
Remove the tyre valve's dust cap and then press the tyre pressure gauge firmly onto the valve.
Check the gauge to see what the current tyre pressure is.
If the pressure is low, inflate the tyre to the correct pressure. The recommended pressure for factory-fitted tyres is shown on the door pillar on the driver's side.
Inspect the tyre for stuck debris, such as nails or other objects, that could puncture the tyre.
Check the sidewalls for any cavities, cuts, bumps or other irregularities.
After adjusting the tyre pressure, remember to store a new reference value in the tyre pressure monitoring system.
If you accidentally over-inflate the tyre, press the metal pin in the middle of the valve to let out the excess air. Then check the pressure again.
Note
Spare wheels may have recommended pressures that are different from those of the original tyres. Always use the pressure recommended by the spare wheel manufacturer.