Freewheel Shiftable Uni?

Couldn’t someone make a unicycle similar in design to purple phaze, but use a front deraillier and have 2 settings, a freewheel and a fixed cog? I can’t see any major problems. If you used the same size wheels, the shift would be smooth and the tension could be pretty high. This would allow you to cruise along normally then shift on to the freewheel and try to caost.

Hmmm one problem I just thought of is chainline…but thats overcomeable.

Front derailers suck though, one little bump and they are all out of wack.

Personally I cant make this kind of a design work in my head, but I also have not had an opertunity to really look at the workings of the purple phaze to see where extra slack is taken up. I assumed it was a fixed gear set up with vertical drop outs to adjust tension on the chains. In that kind of situation I dont know if it would be possible to shift. Do you have an idea of how to tension the chain w/o a rear derailer kind of system, I would assume you would need one with some heavy duty springs to be able to keep the tension where you want it.

I guess you could use a singleator with a wide wheel to cover both “gears.”

I was thinking that an easier solution would be to create a way to lock the spindle to the hub and disengage the jackshaft when you want to ride a fixed gear. I’m not sure the best way to do this, but it seems simpler then shifting the gears.

right again, Daino! the easiest way is with a sprung lockpin on the hub shell that can be pulled out to freewheel, and the spring will push it back in to lock the hub again.

No one has been able to design a fixed gear with any kind of useable idler spring. You’d be surprised how much backpedal force we can create, and the chain looseness required to shift precludes the tension required for a chain-driven fixed gear.
But then again someone please build a shiftable external fixed gear and prove me wrong…!

What if you used a nub button type thing to disengage and engage the innards. Similar to the Shlumph unis.

ive thought about this and i have been thinking it wouldnt really work because when you are engaging back into riding mode from coasting mode the pedals would start to have to turn when you engage