Swappable Hub Idea

I mentioned this idea in another thread and it got no response, but it seems to make some sense to me, so I’ll try again.

The idea is a swappable hub. I really have the Schlumpf in mind, because its cost is more likely to make this desirable.
As usual, the hub shell lives in the center of the wheel, attached to the spokes. But the hole in the hub shell is much bigger than usual and accepts a hub “cartridge”. The cartridge is a sealed cylinder that slides/twists and locks into the hub shell… somehow. The cartridge would look like our current hubs but without the flanges, and with some threads or splines for connecting to the hub shell. Kind of like a bike’s bottom bracket I suppose. Once connected, the hub would look like a typical hub, only inherently bigger. Attach your crank arm(s) and off you go.

So now you outfit your 24", 26" and 29" muni with these special hub shells and purchase a single swappable Schlumpf.

Does this idea have any merit? Pros? Cons?

I posted about the same idea here a little while ago;

Sadly, there didn’t seem to be a great deal of interest, but then I guess it is a pretty niche market really.


Cool. Great minds think alike.

From that thread, it sounds like MuniSano and munirocks also had this idea.

It’s a bit discouraging. Now that I see the idea has been out there and little excitement has come from it. And I don’t expect much has changed in the last year to make it any more desirable.

I still think it’s a good idea.
One problem would be increased weight, though.
The total weight of a Schlumpf is 2.8kg if I remember correctly.
Another shell around that would probably add another couple of 100 grams to that. But maybe the Schlumpf could loose some weight in it’s own shell area then to bring down the total weight again.
I know I would have made good use of this system by now swapping hubs between the 36" and the 26". I am currently waiting for the replacement hub for the 26" and thought about taking the Schlumpf out of the 36er and put it into the 26er. But the way it is now it’s just too much of a hassle.
So yes, I think this idea should really be developed further.

Cool idea! that would make me more interested in getting a Schlumpf, I didn’t relise they were that heavy!

You know, I really liked the idea of a geared hub when I first heard about them, but my interest has dwindled. . . isn’t a geared hub kinda defeating the idea of simplicity?

One of the reasons I ride a uni is that it is is such a simple machine, even compared to a bike, yet could still be considered a vehicle (especially if you’re riding a big wheel) . . .

at some point, I just want my unicycle to be a unicycle. . . That’s not to say that I wouldn’t have a geared on in my stable if I had the money, but I would hope that a geared unicycle won’t become the standard : ( that’d be disappointing.

But to be interchangeable hub “cartridges”, each would have to be self-contained to some degree, which would always make the overall unit (inner and outer hub) heavier than a normal one would be.

Yes, possibly more than you realize until you have to fix or adjust one. But think of it this way. Though you’re complicating the mechanism, you’re enhancing how hard it is to ride. Doesn’t that kind of balance things out? :slight_smile:

Changable hub

Does anybody remember the old Borg Warner 3 speed cranks that you could add to the bicycle? Gearing in the crank, Like the outboard disc brake idea.
Come on people think, we can do this!

I think this would be great and hope there will be more input this time the idea came up.

Does this idea have any merit? Yes, I think it’s a great idea. A schlumpf would be much more justifiable to me if I could move it from uni to uni.

Personally i would preffer to work a bit harder and save up for another Schlumpf hub and have 2 different geared unicycles then have to swap out a hub before every ride. When you consider you would also have to take off a crank (and that means the shifter buttons too), move it then set it back up again- and also considering the moment cranks take a while to seat properly on the schlumpf axle makes it a time intensive endevour.

A top of the line geared Distance or Muni still costs considerably less then an equivalent road or DH bike and saving for one should not be out of reach for most people if they are committed enough for it. Anywho, i am a muni rider and don’t really want a geared road machine (my $50 road bike will always be faster and easier to use for commuting) and am uber happy with my kh schlumpf hub.


Yesterday I had an email exchange with Florian about this idea. My goal was not to try to convince him it was the way to go, but rather to make sure he was aware of the concept. I pointed him to this thread and the previous one mentioned.

He said he was concentrating on making the current manufacturing process faster, to increase volumes, and thus lower the cost of the current hubs.

I then tried to explain the idea that one Schlumpf core and 3 hub shells would hopefully be significantly cheaper than 3 of today’s Schlumpfs. And I suggested the required cost reduction in today’s Schlumpf would have to be significant.

He seemed to be more interested:
“thanks for the detailled infos. Now, I have understood!
I’ll think about it, how we could implement this…”

I was also sure to remind him of some of the risks that have been mentioned:

  • extra weight, and how this affects demand
  • extra costs, and how this affects demand
  • any issues regarding regular swapping of crank arms and/or Schlumpf buttons
  • is there enough of a demand for this?

So, who knows where this is going. If you have more thoughts on this concept, pros/cons, thoughts on the demand, or any thought that you think will help Florian make decisions on this, be sure to post them!

Good to know that he does read his e-mail… Apparently he didn’t feel like answering my latest question about when he would finally send my replacement hub. It’s been about 2.5 months now and it isn’t a repair… Sorry for the threadjack but it’s a little frustrating. I’ll have to call him again, I guess.

It would be cool if he came up with a solution implementing the swappable hub concept.

It would be even cooler if he could half the cost for one hub :smiley:

That would be cool. So a hub would be about $700 instead of $1400.
But if that were possible, and if swappable hubs were technically possible, the maybe it would be possible to make a swappable hub core for $700. And then each hub shell for say… $100 each. So you could outfit 3 geared unis for $1000.

I think I’ve gotten used to the sticker shock of $1400. It’s not such a shock anymore… just a fact. I bet I’m not the only one. So any price like $700 seems sweet.

But in actuality, if the Schlumpf was $700 from the beginning, I would have felt the same sticker shock. $700 for a single hub!! :astonished:

I’ll admit that I’m more frugal than the average person. But to me, the price would have to come down to like $300 before I wouldn’t stress about buying multiples.

Just wanted to say Florian replied to my e-mail now after I forwarded the original message to info@schlumpf.ch. I had sent it to schlumpf@schlumpf.ch first and didn’t get an answer. So maybe people should know that the latter account is not the one to send your e-mails to if you expect it to be answered.

Thanks for the hint, MuniOrBust!

+1 to the general gist of this thread – I’d be much more interested in a Schlumpf hub if I could easily swap it between multiple uni’s.

But I’m also concerned about the weight, as it seems like some kind of splined sleeve would be necessary, which could get heavy quickly. In addition, with the necessarily wider hub, this would move some of that weight outward, so I believe it would also add relatively more to the rotational mass.

Unfortunately, adding more complexity means more design and machining time. It would increase the cost of the hub.