is it true a 3 speed uni with no chain and is bi directional and has the ability to shift on the fly
is this out there and if not is it possible
I’ve ridden a 2 speed… Don’t know about 3 speeds though.
geared unis are around, but tough to come by. perhaps if you rephrase your question in english we’d understand?
3 Gears
Do you know of the three speed bikes your parents rode, they have 3 gears in the hub, you could easily use one of those hubs if you locked the freewheel, you could make it in to a 3 speed geraffe!.
Ollie 
you can convert a bicycle 3-speed freewheel hub gearbox into a 2 speed gearbox with direct drive to build into a giraffe, see http://www.sheldonbrown.com/awfixed.html but I don’t know anyone who has done this on a unicycle.
jim
I’m not sure, but I think those hubs require some play in them in order to shift. In other words, when you’re riding the bike, you have to coast a bit to get the gears to change? Maybe not, but what I do know is I’ve never seen a unicycle made from a shiftable (bicycle) hub, so I assume there is some technicality that makes it unworkable.
the awnser…maybe
yes this is “out there” but it only has two gears its called the Schlumpf Geared Unicycle i’m sure there was a three geared Schlumpf but i couldn’t find it anywho heres the link: http://www.unicycle.co.uk/shop/shopdisplayproduct.asp?catalogid=734
take a look it might be what your looking for
If these are the old Sturmey Archer hubs, you could also get a 4 speed version. My mother still has one. Don’t know if anyone has managed to modify and fit one to a uni though. As you say freewheel would need locking. If it were not so far from here I would check for play on the gear changes. If I remember correctly, you had to freewheel to change gear, but it is a long time ago that I last rode it so could be wrong.
Nao
7 speed hubs are also now available for bikes, and could possibly be used for a giraffe. The problem wiht a three geared shlumpf style hub would be changing gears, currently you press the button in one one side or the other, trying to move it only half the way in or something similar would be pretty tricky.
This came up on a thread a while back. In theory it’s possible to modify a four or five speed Sturmey Archer hub into a three speed fixed hub, but there are reports that many bicyclists find there is too much slop, which is a bad sign for its usefulness on a unicycle. It’s quite a bit of effort to do the modification, so I doubt if anybody has tried making a unicycle this way.
Rob
EDIT: Here’s the old thread
I’ve got an old bicycle with a sturmey-archer 3-speed. Shifting will sometimes work while pedaling, but it usually requires coasting, and sometimes back pedaling just a tad to get the gear to engage. You also have to adjust the cable just right to get all the gears to work in sync with the gear changer. If the rear wheel starts to slip on the dropouts a little, the 1st gear position randomly switches between 1st and 2nd gears and the 2nd gear position randomly switches between 2nd gear and freewheel (I’ve wrecked a few times from this happening). Needless to say I prefer the simplicity of my commuter uni to the speed of my bike.
I’ve ridden many bikes with 3 speed Sturmey Archer hubs, and one with a 4 speed Shimano hub. To change gear, you need to easy the pressure on the gear train by pausing/freewheeling for a moment. The lever/twistgrip has to be adjusted just right.
The hubs are built to work in one direction. The gears are cut to mesh with a certain amount of play.
Any hub gear for a unicycle would need to be purpose-made, or would be of very limited application.
I’m not convinced that gearing a uni is useful. Fun, maybe, but I see no practical application. Why choose a unicycle then try to make it perform like a bike?
I know one big reason - which is to make it possible to ride two different types of terrain on the same unicycle. For example, some people don’t have cars to get themselves to muni trails, or prefer to ride to the trails when possible, for them a high gear to get to the trails and a low gear to ride them is a great idea. Or if you use a unicycle to commute on, it’s great to be able to ride muni on the way, but generally boring to ride a really slow muni to work. Basically, it’s potentially useful if you’re not someone who always drives before going riding, and you use a unicycle as a mode of transport rather than just something to play around on. It’s also a great idea for muni rides, because however well you plan, most long muni rides involve some road / forest track or easy singletrack riding that would be much more fun ridden at high speed.
For me, even pretty easy muni riding like Bramcote is a bit dull on a coker, especially with 110 cranks for commuting, you can’t ride the best bits, only really the across trails. Similarly, my commute takes ages and bits of it are way slow if I ride on the muni.
Joe
Fair points well made.
Even if one of those fixed 3 speeds would hold up, I’d like to see how the shifting chain could be integated in with a modified axle that could accept cranks. I think we better count on Florian and Kris.
I think it would be used with a giraffe. BTW pdc, wanna go riding sometime? I graduate in a few weeks, and would love a trip up to the mountains.
I’d love to. Give me a date and I’ll try to set aside a Saturday or Sunday. That house is still vacant, we’re not moving back there till July. If you and any other riders wanted to make a weekend out of it you’d be welcome.
Hey all this doesnt really relate much but just a thought i had to day, could you add the effect of gearing to a uni by having a device that, ideally lets you change the lenghts of the cranks on the fly, by allowing them to extend on a teloscopic principle (or something cleverer), or at worst have to dismount to change gear by manually adjusting crank lenght???
This to me just seems an easy way to gear a uni cyle at low costs, so that leads me to belive i have missed a huge chunk of logic and this really cant work, well effectivley anyway.
Firstly would this give the effect of gearing to the unicyle, secondly would it reduce the integrity of the cranks and finally would the varying crank lenghts makes the uni very hard to ride.
ps: is this just a rubbish thought that has been dreamed up many times an just never done due to the stupidity of the idea??
please some one let me know.
I have never heard of this,. but it seems like it would work, only problem i really see is that your cranks would be hollow which could lead to them breaking easier.