Originally Posted by
Siu Blue Wind
Wow this is cool. Can you explain how the black disc pushes the der please? It's hard to see how it would get it to the smaller gears. How do the weights moving outward affect the center black disc? Or perhaps a closer pic?
The derailleur is sprung in the reverse direction of a normal derailleur. With no input it pulls the chain all the way left onto the lowest gear. The derailleur rides against the pie plate (black disc) which is conected to three weights placed between the hub and the rim. As increased speed pulls the weights out, the pie plate moves right, pushing the derailleur and chain into the higher gears.
What looks like a normal 6 speed freewheel is actually fixed onto the hub. The "freewheel" is in the front chainring assembly, which allows the chain to run (and gears to shift) any time the bike is rolling, even if you are not pedaling. Every time you roll to a stop, it will automatically shift back to the lowest gear.