Thursday, March 1, 2012

Getting ready for the second road test...

After I rode the handcycle on a trainer for a few hours in order to "get the kinks out" relative to cabling, braking, changing gears, and spinning, I was able to diagnose a few minor issues.  Specifically, I had to align the disc brakes and calibrate the cables. Additionally, I decided I had to build a more substantial cable holder since I was able to break the temporary one off pretty easily.  And finally, I decided to build, with carbon fiber, a holder for the speedometer/odometer pickup that sits on the fork.  The speedometer unit that I purchased is a cheap wireless one.  Therefore -- due to wireless nature -- the pickup has to sit fairly close to the rear of the fork.

But the bigger problems displayed their ugly faces when I removed the handcycle from the trainer and attempted to get on it and move it forward.  The front wheel easily "flopped" to one side.  This is not an unknown problem with handcycles.  Since a handcycle's front fork usually has an integrated crank, bracket and steering, the fork can have much more severe problems than those encounter by the typical bike.  I found it quickly: A flopping fork in which the bike's front wheel attempts to lay itself flat to the ground...

I decided upon two courses of action to relieve this problem: (1) Adding a self-centering steering mechanism and (2) adding "stops" on the steer tube holder that only allow the fork to turn a maximum number of degrees before confronting the "stops".  Therefore, the maximum flop can be controlled by the size of the "stops".

Both the stops (left and right) and the self-centering mechanism are in place.  I have some cosmetic work to do on the frame after the changes -- but those are much more minor as compared to the additions.  Here are the pictures:

1 comment:

  1. BTW, this carbon fiber handcycle is about 1 mph faster on a trainer over a two hour workout than my aluminum one. There is so little give in the uni-body construction that I am NOT expending my energy flexing the seat and frame. The output goes directly to the wheel. My guess is that the wheel is receiving about 15-18 watts more of output.