UNIQUE TREADLE DRIVE BICYCLE

This is my version of W B Smith's 1917 unusual Tasmanian patented bike.

The objective of this project was to recreate a treadle drive using modern one way clutch bearings. The problem Smith had was that ratch type clutches have 36 teeth (similar to modern rear freewheels) this mean that every change of direction there is a lag of 9 degrees. Since you are only driving through an arc of 120 degrees this amounts to 27 degrees per revolution not very efficient, where as modern clutch bearings are instantaneous.

The rope returns the opposing pedal, alternately you could use toe clips to give the same result. Drive can be achieved by alternate downward strokes of any arc or both pedals together. I have moved the pulley so the rope naturally limits the stroke without using energy absorbing springs. 

Tech info 52t chainwheel, 19t rear fixed cog, 225mm pedal arms, two Tsubaki cam clutch bearings (35mm id. 173Nm torque capacity) and a 1920's high centre bracketed long wheelbase bike.

  created by Ross Harrop. Have fun, Go to it. You're on your own in a big standardised bike world.