Monday, February 13, 2012

Building the handgrips / pedals

For me, the pedals of a bicycle become the handgrips of a handcycle.  For my handcycle, I am building these from scratch since there is no commercial product that matches my specs. Those specs are:

  • The right handgrip must contain the gear changing mechanism for the hub transmission.
  • Both grips must accommodate brake levers (Often only one grip contains a brake lever since the second brake on a handcycle is normally considered a "parking" brake. I consider this layout inherently unsafe).
  • Grips must not be constructed to be out beyond the width of the knees (as many handcycles designs do).  I would like to keep a more aerodynamic shape to my body.  One can imagine the disadvantage a time-trialist or triathlete would have if their body position required that the hands be well wide of the knees.
  • The bearings must be easily replaced.
  • The grips must conform to the hand. A cyclist can only image the discomfort if the cyclist had to put in a century without shoes.  Even if the bicycle's axles are big tubes in order to have a larger surface area against the foot, the cyclist would soon find discomfort in his/her feet anyway.  For me, my fingers cramp up quite often.
  • The grips must have a fairly large surface area.
After I built the tubes (previous post), I fitted the tubes to one another and to the urethane foam plugs that represent the grip's forms.

Then the tubes had to be fitted to one another.  This required a Dremel, rounded file and patience.

The parts brought together:

Putting it together before the carbon fiber exterior is formed:

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