The second part of the law says that the 1.6mm measurement must be across the central 3/4 of the tyre - see above
This means that at any point across the main part of the tyre, the tread depth MUST BE NOT LESS THAN 1.6mm.
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.