A recent graduate from the University of Louisiana at Lafayette, James Breaux has come up with a pneumatic system that will replace the chains on a bicycle. Movement of the pedals makes compressed air push through the chain stay which turns the wheel. When the bike is going downhill, the air gets stored inside the main chamber of the frame through a flywheel system which acts as an air brake apart from providing a boost during uphill pedaling. The bike’s frame is manufactured through a process called super forming (vacuum forming metal heated to very high temperatures) while the tyre tubing can be made from lighter and completely air-tight rubbers. Interesting concept, though I would really like a prototype testing to dish out a true comparison between the pneumatic and regular bikes.
Source: Bicycle Design