Tubeless valves are generally made from rubber with a central core of metal containing the components required for inflating / deflating the tyre and providing the air seal. The valve core provides the primary air seal in a tubeless valve, a secondary seal is provided by the valve cap that also acts as a seal to prevent the ingress of dust and moisture into the valve itself.
Different types of tubeless valves are available for different applications / requirements. Usually available in two standard lengths the shorter one is generally used for alloy wheels and the longer one for steel wheels fitted with a plastic wheel trim – longer length allows for the valve to be accessible without removing the trim.
You will also find another type of valve that is mainly constructed from steel. These steel valves are bolted into the wheel and are usually found on high performance wheel / tyre assemblies.
Standard snap-in rubber tubeless valve
Metal bolt-in valve
Standard plastic valve cap
High-pressure valve cap
A rubber tubeless valve will, over a period of time deteriorate. It is therefore recommended that whenever new tyres are fitted a new tubeless valve is fitted, too. Also whenever a tyre is removed from the rim (puncture repair etc) it is again recommended that a new valve is fitted. This is due to the fact that the base of the valve may be damaged during the removal of the tyre from the rim.