Awesome!! Is that about as short as you figure it could go? Looks like you’re right up to the part on the arm where it starts to get thinner in the centre.
I’m holding out for a 95mm disc brake setup! But this is progress!
I could have taken them to 100 mm with no problem. I did not consider anything shorter. The crank arm is reasonably thick at that point, and I would just flatten the top surface before cutting the hole for the taps.
The whole project just took one evening, but I would not attempt it without a drill press.
Scott
Wow. Amazing. Haha are you taking orders?
Do You want a pair? I hear you are going on a long ride soon. 
I could cut some 60 mm cranks for you. Wouldn’t that be a blast!
Scott
I do! Haha but not for that particular ride. Thinking about another tour this summer. Maybe Canada again, or part of it. Maybe Iceland.
I’ve been drooling over the MU system since it was announced, but it’s only attractive to me for very short cranks. Now I’m really excited! DM on the way. edit: I mean PM. This isn’t twitter…
The Nimbus disk setup is going to be available at the start of April which will accept any cranks…
Despite my original interest in the mountainuni system, even with changing the hub and new spokes and wheelbuild (that I’ll probably do myself anyway), the Nimbus system is very likely to work out cheaper as it doesn’t need the expensive custom disk. As neither are really Schlumpf compatible I don’t think the lack of being able to use a Schlumpf with the nimbus system is really an issue.
If it is then you’ll have to wait for KH to release his disk-on-crank system in June/July which presumably will be fully Schlumpf compatible.
[QUOTE=mowcius;1507376]
The Nimbus disk setup is going to be available at the start of April which will accept any cranks…
Despite my original interest in the mountainuni system, even with changing the hub and new spokes and wheelbuild (that I’ll probably do myself anyway), the Nimbus system is very likely to work out cheaper as it doesn’t need the expensive custom disk. As neither are really Schlumpf compatible I don’t think the lack of being able to use a Schlumpf with the nimbus system is really an issue.
If it is then you’ll have to wait for KH to release his disk-on-crank system in June/July which presumably will be fully Schlumpf compatible.[/QUOTE
Mowicus, you need all the facts which I don’t believe is available yet. That hub and bearing mount alone, when released, will likely cost more than a complete MU kit. My customers have mounted their Schlumpf hubs with our UCM, and kits and they work great, no issues. There can be some teething pains with the setup, but We’ve said all along that you should have some solid cycle mechanic skills, or have install done my someone who does. I’m not saying that Florian enforces our product, nor would I expect it with the existing business relationships and commitments in place with UDC and KH. But it is compatible, just not endorsed.
I do like the debates, and also the competiton. My system uses existing ISIS hubs and your current spoke rim setup. The economics are pretty simple.
Nice work on the crank chopping Scott. There are plenty of cranks in stock for those looking to experiment with something similar :-).
My guess is that the 100mm Nimbus disc hub will be the same price as the Oregon hub (the same thing, just wider) and the Impulse hub (wider and Aluminum axle, instead of steel) at $135. The bearing mount is $30. That doesn’t include cranks, but a MU setup doesn’t include a hub… (though you probably already have a hub on your unicycle)
- Spokes
- wheelbuilding
but anyway, this design will result in an less stabile wheelset, cause the assymetric and more narrow hub flanges. may be not so big issue with 24" but 26"? 29" 
and 36" 
we (the ridetriton team) developed an even more stabil different flange diameter disk hub, which allows to build a symetric wheel but stopped this project two years ago, cause the Mountainuni system allows a normal stabile wheelset.
last year I killed two KH titanium hubs but only one pair of sinze cranks…
we will see
- whatever, the most riders wont have problems with stability.
Clearly there are pros and cons with both systems. I have the MU system on my 36 and it is awesome, but I’m going to build up the nimbus hub in my 26 muni. The ability to use a real bike disc is very appealing because I have had some issues with the MU setup due to how thick the disc is. For one, if you bend it on the trail, good luck bending it back with your hands.
It’s too bad the crank design didn’t get produced. Being limited to one disc and one type of cranks strike me as the main problems with the MU system, particularly where either or both of these options could disappear at any time. A lack of relaible sources for replacement parts is a major problem. And nothing personal guys, but the delay on product delivery followed by inability to produce the cranks doesn’t exactly instill confidence.
That trully stinks that they couldnt produce cranks!
I am not sure I see the issue with Sinz cranks. They are readily available for a modest price:
I have never broken a crank, so once I set up the system it should last me for years. The only limitation is the minimum crank size (135 mm), but MU will customize cranks for you or you can do it yourself. The MU disc brake itself works great.
What is the problem?
Scott
I was given rough pricing but I had forgotten that the mountain uni setup has gone down in price and was messing up my conversion from USD to GBP slightly but still not a lot in it.
Google gives “Able to exist or occur together without conflict” for compatible so I’d say it works but isn’t compatible.
I have to admit that if there was the ability to fit any size disk (with a standard crank disk mount) then it would be that bit more appealing. It is a shame that the custom crank idea is not to be but I can’t imagine that it would be cheap to produce a small run of custom cranks.
The MU system is definitely compatible the a schlumpf. However, it takes some extra work for that to happen. Florian has not endorsed the setup though…
“definitely compatible”?
Where the manufacturer of the hub says the hub cannot be used with spacers, and spacers are necessary for use of the brake system, that does not seem “definitely compatible” to me. See posts 882-887 on pages 59-60 of this thread. I think it would be very unfortunate if someone read recent posts about a guni being compatible with this system and then destroyed their hub. No, that doesn’t seem to have happened to anyone yet, but potential users should at least be given full disclosure of the risks and Mr. Schlumpf’s recommendation against using spacers because they can destroy the hub’s bearings.
What extra work is that? Which side do you have the UCM bolt onto? Presumably not on the same side as the torque bearing?
That assumes that people use spacers with them, but I don’t think they do, from what I’ve seen so far.
I thought use of a spacer is the only way to keep the disk alignment stable, i.e. avoid crank creep?
From what I have read in all these pages that is the case.
Glad I’m not the only person who remembers the comment about not using spacers.