Shimano have released their “Airlines” downhill specific pneumatic shifting system to consumers in the US. Shimano Airlines actuates the derailleur by flipping a lever using the power of compressed air so shifts are, apparently “always fast, smooth, and responsive regardless of your energy level or attitude.”
The system is powered by an air tank that is carried on the frame just like a water
bottle. The tank uses a normal Schrader valve so air pressure can be “topped
up” with a hand pump or at any petrol station or bike shop. The 500cc air tank
carries enough air for approximately 400 shifts. An air regulator provides for adjustable operating pressure that can be easily read at the pressure gauge.
Full details of the system can be seen at http://www.shimano.com/cycling/mtb/airlines
We have no details of UK availability at present.
All images (c) Shimano American Corporation 1999