Wednesday, March 27, 2013

Yet Another Design

Right Side

Why another design?  I would like to change a few things on the newest handcycle.  These include:

  • Move the seat closer to the ground in order that I am more comfortable with my hands to the ground at stops and that I can crawl on and off the bike more easily.  
  • Get rid of the chain running between my legs (that required a chain guard!).
  • Change the fork design relative to the headset bearings. I would like the bearings to not have the "give" or play between the fork and base that the ones I have used permit.  In particular the bearing in the existing fork use a rubber seal that must be compressed.  For the new design I will probably use the same bearing that I use in the retractable wheels' axle.  They are indeed solid. 
  • Design the neck of the base to have an interior "beam" of carbon fiber in order that I cannot produce deflection in the bike's neck when powering up the handcycle.
  • Move to a larger rear wheel for comfort sake (650c or 700c).
  • Allow more room between the chain and the neck of the base especially during turns.  The existing bike's chain-neck interaction is problematic during startups when I may suddenly steer pretty wide in order to maintain balance. Again, this occurs at very low speed. At higher speeds, the handbike can lean into turns (with the retractable wheels up).  Of course, now that I have the retractable wheels the steering/balance problem at initiation of movement may alleviate itself.


The most obvious change in the design is relative to the chain.  This new design has two chains -- one that runs nearly horizontally and another that runs vertically thus removing the problem of the chainline.  The latter chain is hidden by the chain guard enclosure.

I am testing the retractable wheel design on my current handcycle.


Left Sde

The design will probably change before I have a chance to build it -- but that is the nature of design!

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