Schlumpf gear-change unicycle hub prototype revealed

Greg has some competition!

That looks pretty cool. The nub from the shifter doesn’t seem to protrude as much as the KH so that shouldn’t be an issue.

If it can be used for Muni, that would be great. Many times on the flats I wished I could go a little faster.

Wow that looks cool.

It’ll not be cheap though, the standard bicycle version is over £200, ($412 + postage + taxes for you guys in the US).


This would be more practical to fit to a coker than the current shiftable hub, the shifting on the fly would mean you could start off in a normal gear and then shift up once you were going.

Mmm, a coker or 29er with a normal cruising speed of 20mph instead of 12 would be great.


Does the shifting on the fly by hitting it with your heel worry anyone else? It seems like it’s in just the wrong place for an accidental shift. How would you like to be riding along at the 1:1 ratio and suddenly you are unexpectedly at 1:1.6?

I got e-mails today from Florian Schlumpf, the hub developer, and Peter Eland, the editor of VeloVision magazine concerning this article. Peter sent me the print issue. This looks really cool. Unfortunately, the photo I’ve seen doesn’t show the business end of the hub but Florian indicates that he plans to go into production so he may not want to expose the whole package. He started development because “several unicyclists” contacted him recently. I wonder who those could have been?

Familiar looking package, eh? I’m still haggling with overseas manufacturers and Florian probably has more experience along those lines. Unless he builds it in Germany which will put a huge pricetag on it.


I’ve got a Speed Drive on my recumbent, and accidental shifting is a non-issue. I’ve installed the “Easy Shift” levers, and it still takes a purposeful tap with the heel to shift. Less than purposeful though, and you can hit an in-between spot where the pedals just spin.

I don’t think it would be easy to shift “on-the-fly” unless you did some serious practice. Even on my bike, I “pause” or slow down pedaling to shift. To shift the uni hub would probably require a still stand type move, with cranks at 3 and 6 o’clock.

The big advantage is that no tool and no dismount is required to shift.

The frame in the photo on velo-vision has some pretty spindly legs to it. Some method of attaching a torque arm will be required, as on Greg’s hub.

Very cool indeed

that is pretty cool, i remember seeing this article and thinking that it could be pretty easily adapted to a unicycle hub

Re: Shifting

On a unicycle, due to the fixed nature of the hub, won’t the easiest way to shift the hub be to kick it across while you’re pedalling at exactly the same speed as the wheel is turning?

Or is it purely the hassle of moving your feet to the right place that makes it hard to shift, rather than anything to do with the amount of torque on the gears making it harder to push across?


Re: Re: Shifting

The Speed Drive is shiftable under load, so shifting while pedaling is normal. However, it does take slightly more effort to shift. The shifting motion involves pivoting your foot on the pedal at the proper position of pedal stroke to hit the shift button. “Easy Shift” levers make it easier.

If you’re at speed, say 80-100 rpms, this will be difficult to perform, but not impossible. I find for me, it takes conscious effort to nail the shift at this rpm, and I think on a uni, this would cause me to UPDWS (Unplanned Dismount while Shifting).

Or, should that be Unplanned Dismount while Schlumpfing?

Re: Shifting

OOPS. Should be 3 and 9 o’clock.:stuck_out_tongue:

YIKES! 412$ for the bike version! And that thing has a huge marked compared to the unicycle hub.

Oh my goodness! That was Nick Green, a fellow Brisbane unicyclist. He contacted Schlumpf about this ages ago and their reply was, “Actually, we were just thinking about adapting our system to unicycles!” A little suspicious? :slight_smile:


Did you guys know that ‘Schlumpf’ means smurf (the little blue guys with white pants) in german? It must have been interesting going through grade school with that one.

Cool hub! i hope i get to try one someday.


Throw one of these on a Coker and a 15 MPH cruising speed in now somewhere around 22 MPH. Shite! That’s something to get excited about.


My deepest apologies for misrepresenting Florian Schlumpf who is of course Swiss, not German.

That’s something to be frightened by. Imagine UPDing at over 20 mph! Ouch.

then again, cruising at 15 MPH would require a much slower cadence with the new hub. That would be nice.

I thought that all unicycles already came with two gears, Forward and Reverse, although not all unicyclists can engage reverse and I’m one of them.
A geared unicycle seems like a good idea if you like that sort of thing but to me seems to be removing itself from the pure simplicity that is the appeal of a unicycle, if I was to add gears and a brake then I may as well add the second wheel and be done with it. But then I will never be brave enough to go at 20mph on one wheel…

This is indeed an interesting development.

The Mountain Drive and Speed Drive are neat. I tried them on a stationary bike at the Seattle Bike Expo. Nifty cool little things.

I’m a little worried about price though. They aren’t cheap to begin with and the unicycle version will probably be more due to low volume.

I hope it will work with our regular unicycle cranks. It is supposed to work with normal cranks, but the crank does need to sit on the tapers just right. Not too far and not too little. Too far and the shift button will stick out too far. Too little and the shift button won’t stick out far enough. Standard unicycle cranks are not always the same in this regards as regular bicycle cranks.

I’m slightly worried that there might be some unintentional gear shifting when your foot accidentally rubs against the shift button. I have a bad habit on my Coker of having my heel get too close to the crank and rubbing. This may not be enough to cause it to shift completely to the next gear, but it might be enough to cause it to get partially out of gear. I’d rather have the shift button recessed so that you have to stop and dismount and push the button in by hand in order to shift. Shifting on the fly is not going to be very practical anyways. It’s not a great problem if you have to stop to change the gear.

Removing the crank takes a little more care than with a normal unicycle hub. Installing the cranks also takes more care. After reading the tech manual for the Speed Drive, I don’t want to be changing the cranks much at all. Changing cranks is not just a wham bam thank-you mam operation like it is with normal unicycle hub.

The tech manual for the Speed Drive is here. It’s an Adobe Acrobat document. It’s got details on what’s involved in changing cranks and other tech details.

Harper’s has the potential to be less expensive (iff the Chinese can build the thing correctly) and also less complex because there is no on the fly shift button thingy ma bob. Harper’s hub will also work with any square tapered crank that we use for unicycling. I don’t know if the Schlumpf hub will work with all of our favorite unicycle cranks.

Still very cool.