The correct pressure is important both for safety and for a long tyre life. They must be checked when the tyre is cold (By cold we mean the ambient outside temperature where the tyre is to be used). Tyre pressures must be checked regularly, about once every two weeks.
A drop in pressure can be caused by:
- the natural leakage of air through the walls of a tyre,
- drops in ambient temperature,
- small perforations that, in a tubeless tyre, may not lead to immediate deflation but rather deflation over time, (a slow leak!). This in turn can lead to irreversible damage due to the tyre running in an under inflated condition.

Should I put Nitrogen in my tyres instaed of air?

Nitrogen is commonly used in racing car tyres, because it has a consistent 'volumetric expansion rate' as the temperature changes, which means you can predict how much it will expand as the tyre heats up.

Air, on the other hand, readily absorbs moisture, making it impossible to predict how much it will expand in the tyre.

The height of a racing-car tyre is critical and any error can cause handling difficulties and ground clearance problems. For ordinary road-users, the potential benefit is slightly different.

Nitrogen cannot permeate the pores of the rubber as quickly as the oxygen in air does – so tyres filled with nitrogen are much less likely to deflate. As many owners don't check their tyre pressures regularly, this could benefit them.

Maintaining consistent tyre pressure, in line with the makers' recommendations, helps with wear, comfort, rolling resistance (hence fuel economy) and noise.