Was getting worried that this project died silently. Thank you for your enthusiasm, it’s what this sport needs most.
Awesome project! I too was apprehensive that Justin had lost interest and moved on.
Keep the innovations coming, and if you’re ever out this way, I’d love to give it a try!
No, well sortof. I’ve already got my head and parts procurement working on the next jackshaft geared uni build. Which will, if it all works as I think it should, be the holy grail of guni!
I’d love to be out that way too, copenhagen is high on my list of cities to visit. I will at least be going to France this winter with An’So and could bring it along with us then for people to ride if there’s enough interest.
Justin
This is really amazing. I’m no engineer, so I’ve had to skip many of the points made, but just watching an invention from soup to nuts (and bolts) is really exciting.
I see that you’re getting plenty of friends to help test it out. That’s great; I just wish I lived closer!
Best of luck, and keep up the great work.
David
Trust me, there’ll be enough interest.
David likes having things shipped to him if he doesn’t live closer. He’s a good tester, too.
Justin, you’ll be welcome with beloved An’So; and don’t forget your Guni !
If you can go to Copenhagen then Cape Town won’t be a stretch 
I’m sure we can scare up quite a few folks to test your rigs 
Indeed!
brainstorming
the idea of brainstorming is to use stupid ideas to let useful ideas bloom
so here is my contribution to brainstorming (I am no mechanics and my drawings are naïve! but as a naïve person I may be ready to finance experiments :D)
uni-gear-brainstorming.pdf (62.9 KB)
It took me a while to get my head around what your proposing.The cranks rotate a ring gear which transmits power via planetary gears fixed to driven axles which in turn drive the planetary gears inside the hub then drives a ring gear fixed to the hub.The basic version would be single speed.Possible issues,the crank ring gear would have to spin on a stub axle coming off the frame and with no through crank that stub axle and frame would need to be very rigid,the hub and ring gear would need to spin on a bearing with inside diameter greater than the radius spacing of the driven planetary axles that would be a big bearing,where would you source the gears required.
The idea isn’t ready for mass production just yet but it does throw a new way of looking at gears for the unicycle.
john
That might as well have read like this:
<feeds quoted paragraph fed into a word-randomizer>
It a then would single greater fixed in crank be version hub.The fixed frame a of
spin to gear driven via turn gear my to driven have a to with proposing.The gear
the required. a gear get the which transmits cranks which planetary spacing to a
rotate very and the would crank gears took axle the inside the hub stub coming
basic on head while power that what than need be around through axle would ring
gears diameter and to on a the to spin need be would planetary stub planetary
would bearing gears and that issues,the big with ring axles rigid,the bearing,
where no axles ring speed.Possible me your ring off inside frame would radius
you source hub drives the drive.
It made as much sense to me!
Burning Man Pics
Well, the 3 speed survived a full week of abuse and crashes with only a few shifter cable adjustments required. Best thing was running into Neptune, who took me under his wing back at Burning Man in 2005 when I was a total beginner still learning to freemount.
Here he is after getting the hang of it just prior to a group uni ride around the black rock city.
any updates on this project?
Hello, after reading all the posts I could find about geared unis I think the best chance to get a multigear hub would be to modify the NuVinci hub. It seems the easiest way creating as few as possible customized parts.
Using NuVinci tech won’t allow it to be sold but if we concentrate our efforts we could make a group to share costs and have the custom parts machined with high precision for a relative low cost.
Using a chain seems a temporary solution for unis and, as I’ve seen, theoretically adapting the Nuvinci would just need a customized roller ramp, unfixing the hub shell to the axle and fixing the sprocket part to the axle.
Then taking out the shields and sprocket to shorten the 135mm length to 100mm and fixing the 42mm bearings with welded nuts with ISIS ends, it would be theoretically ready.
Not sure about the final cost, but if enough people get into it, a <900$ solution including the NuVinci hub price seems possible.
I think this thread its great but maybe we should open a new thread focusing in creating a CVT uni hub.
I know this is an oldish post and you might have worked this out for yourself by now, but as the thread has been resurrected and I’ve read it for the first time…
Except that at the point the hub takes over and spins the pedals at a higher rpm, the clutch is still engaged. It still wants to spin the hub at the same rpm as the sprocket (whilst the hub wants to spin the sprocket faster). This will result in the hub locking up in just the same way as you identified earlier when running two gear sets with different ratios.
No way round this one unfortunately - the only point a clutch will work is if the hub is in 1:1 mode, which kind of defeats the point of a gearing system (if you had a hub which geared up rather than down you’d get the lock up when pedalling forwards).
Sorry, won’t work.
That post appears to make exactly the same point as independently determined by the OP of this thread. The post you’re responding to suggests a solution to that issue (previously also mentioned by the OP) of using a customised roller ramp so that full drive torque can be transmitted in either direction. The remaining issue then is that it seems this would result in a significant amount of backlash. I do also think the use of the word “just” in conjunction with a list of not exactly straightforward procedures is rather unfortunate!
Well, the slippage won’t be so much if we modify the ramp, and the grade of backlash is relative to the forces implied and the allowed slippage. Also the fluid in use has a lot to do with all that. Why not looking for a compromise between them?
Of course it won’t have a perfect grip like a geared one but a little fluid response is not so bad considering the benifits.
I used “just”, because compared to create a whole CVT system, fixing and unfixing those parts is relatively easy by modifying them or creating new customized ones. The Nuvinci system is beautifully simple and taking it as a starting point could be a good way to achieve a real CVT unihub.
Anyway it seems more feasible than magnetic ones 
Oh man, patents surfing is so cool sometimes…
Jw how much did it cost to build?
Wow that is really cool good job tell me if it all works out