View Single Post
Old 2011-03-08, 05:30 PM   #52
rob.northcott
Mainly XC Muni
 
rob.northcott's Avatar
 
Join Date: Aug 2004
Location: Dartmoor, England
Age: 45
Posts: 2,882
Quote:
Originally Posted by kb1jki View Post
...(Geared jackshaft design)...
I still reckon a multi-speed gearbox that is small, light, drives both ways in all gears, doesn't have too much slack/backlash and is shiftable without losing drive would be pretty hard to come up with. Most bike geared hubs can only drive in one direction because they "cheat" by using roller clutches to avoid having to mesh and unmesh gears.

Single-speed jackshaft unicycles have of course been done, as I'm sure you know (Pete Perron's are the highest-profile ones from a few years ago).

Given the gearbox would have to be bespoke, I'd suspect it would be just as costly as a Schlumpf. Somebody suggested using a NuVinci CVT gearbox on a jackshaft, but I think they asked NuVinci about driving in reverse and they suggested it wasn't really meant to do that. And they weigh a silly amount! Although a CVT unicycle would be the holy grail of gearing systems - no nasty lurches on shifting.

Rob
__________________
"Hedgehogs - why can't they just share the hedge?" (Dan Antopolski)

"I would absolutely recommend a 29er to anyone who didn't prefer a larger or small wheel." (Mikefule)

Last edited by rob.northcott; 2011-03-08 at 05:32 PM.
rob.northcott is offline   Reply With Quote
 
Page generated in 0.05450 seconds with 8 queries