Video of David riding crab cycle
Video of David riding crab cycle in reverse
Video of David pausing crab cycle
The next logical step after a double wheel unicycle. Also wanted the it to be easily switchable (within a half hour) from pedal forwards go left to pedal forwards go right. David Bagley sent this idea to Tom Miller of the Unicycle Factory. Tom Miller did the hard part turning the idea into reality.
Off the shelf gear box (not used).
Early design, sprocket later moved to be inside gear box. Also bearings for sprocket axle were moved up as there was just enough room.
boring holes for bearings
Starting with 3/4" 17 - 4 Stainless Steel
Cutting cotterless crank axle
3/4" - 16 threads per inch for threading for shaft collar
Cutting key-way slot for miter gears
Axle for Sprocket
Remove excess material 0.300"
Before and after Miter Gear
Fitting of gears
Marrying Sprocket and Gear
Installing roll pits to set gears in place
Thin Miter gear to reduce weight
These clamps allow one to shift from "go west" to "go east" easily.New Aluminum shaft collar
adding the threads 3/4" hole with 16 threads per inch
drill slot for allen screw
was square now round
knerl the clamp
slitting shaft collar
top slot (faint) for chain clearance
amazing it weighs the same, closed or open
25 Year Old Tooling
Narrowing 2" Frame to the 1.5" for the Crushing Cupping Die ("Schwinn")
Drill Jig Stop Guage
Frame Crush Die
learning crab cycle vehicle
Now has a 20" wheel ... just enough room.
Its Yellow! (Tom Miller had it powder coated for me).
I needed about 3 months to learn to ride. For reference, it took me about 1 month to learn to ride the double wheel unicycle.
I practiced along a high fence and have it set to go west (pedal forwards, go left). I kept going from right to left until I needed to hold on less with both hands, eventually brushing lightly with the right hand. One has to lean left, then pedal forwards.
Next I learned how to fall off gracefully (it really helped me gain confidence). I held the right pedal down and let myself drop to the left.
Next I tried to see how far many revolutions I could get without touching the fence. I had to get up to about 40 revolutions, until I felt confident to leave the fence behind.
By 6 months I could ride a figure-eight with it. By 9 I could do a few and also riding by pedaling backwards, this took me many months to learn and found it took me longer to learn than forwards. Then at 10 months I just got idling with right foot down (it feels like a "Manual" or Skateboard Wheely) with the "required": ride in, 25 idles, and ride out. I am quite ambidextrous, but idling with the left foot down is too strange yet (it feels like your balancing on the front wheels of a skateboard, which is hard).
At 11 months, I could reverse direction on the fly. Also got a figure eight while pedaling backwards. And I was was finally able to mount it a few times, with the right pedal down, not too bad once I put my mind to it (knowing idling sure helps). At 12 months I was able to just barely juggle clubs on it (learned first to idle with hands behind my back).
Finally, at 15 months I got some left foot down idles... (ie ride into, idle 25 times, ride out). Just as hard for me, but maybe more impressive is the left foot on box idles. If I start holding on to something, I can do this one foot idle and then get my foot back on pedal and riding away. Still working on consistency and trying to figure out how to get my foot on the box from an idle.
I hope to get more consistent mounting and get better at juggling clubs on it. Also trying full turn of the wheel idles (did about 4-5 ie one full revolution and then reverse).
For 2 months now, I had the mechanism reversed to a "Go East" mode, ie. pedaling forwards one goes right. I was a total beginner once again! It took me a month to learn pedaling backwards and another month to learn pedal forwards. For some reason, I am more "left leaning" it seems. I rode in a circle the various ways and I was learning idling.
Switched back to "Go West" mode. I felt I was not progressing quick enough. After 5 min of disorientation, I was riding again with ease. Today, after numerous attempts, too many to count, I did my first mount into an idle.
Special thanks to Tom Miller for making it possible.