Broken KH/Schlumpf hub

Well, my KH/Schlumpf hub has started to have problems.

It was starting to make some ticking and grinding noises as I rode home today while riding in the high gear. I made sure it could shift through gears and it seemed fine. Then at one point I downshifted while riding and it freewheeled. I took the wheel off the frame and when downshifting it would freewheel for a while before engaging, and would make a click click click sound like a bike freewheeling. Sometimes it would engage if I hit the button a second time. I got a ride home and made sure the buttons where adjusted right and the cranks were torqued properly. I shifted it a bunch of times and played with the button adjustments. Then it stopped shifting at all, either way.

I figured out that the hub’s axle is moving left/right. It moves too far to the left and prevents the gears from engaging.

Low Quality movie (.mov, 1.8 MB):
High quality (

I’ve emailed Florian to ask if he has a solution for the problem. I can’t just hit it into place, as riding (and shifting) seems to move it back to the problem state.

Does anyone else know how to fix this? I may take the cranks off tonight and see if there is something obvious that is missing, which might cause it to slip left.

I’m a little disappointed, as it means I won’t be able to do any training for these last few days, and that I may not have my hub for RTL.



36" unexpected BC wheel :astonished:

Bummer Corbin. :frowning: Hope you get it figured out! I know how it is not being able to train and ride as I’ve been out for almost the last 4 weeks due to broken foot…but should be riding again this weekend. I’ll have one week to train! :frowning:

Now it’s looking like maybe the ungeared teams might have a better chance…

Hmmm, I hope this is related to the previous problem that is fixed with the new batches.

That is bad news though, I hope that you can get it fixed or replaced in time for RTL! I’m starting to wonder if maybe I should have got the standard hub instead since it already had a few years to work out the intial issues that new products seem to have.

Almost certainly isn’t a fix, but is there any chance loose cranks could allow this wobble to happen? Being splined aren’t loose cranks a bit less obvious than square taper?


How many miles have you done on it?

Perhaps there should be a required maintenance log for Schlumpf hubs. Eg after a certain amount of use they are all pulled apart and serviced. And after a certain amount of usage to replace all moving parts.

A Schlumpf hub is a bit like a plane…extremely reliable but you never ever want anything to go wrong in mid-flight.

I dunno whether servicing would help much with these problems people are having - because any sensible service interval would be way higher than the distances people are breaking the new hubs in. I suspect it’s more an example of very high stresses 36 riders put on the hubs, which have only previously been tested on 24/29, and the need for the hub upgrade & recall. I know my old 29 hub seems to be working fine, and that’s been ridden easily 4000 probably 5000 or more km, but I guess I must put way less stress on it than a fast rider on a wheel that weighs 2 or 3 times as much as my 29er wheel.

Although that’s obviously all conjecture, I know very little about the internals of my hub, and nothing at all about what’s different between new and old hubs.


True, but I would still propose that there is some sort of recommended service and replacement interval. Moving parts wear down eventually. A bikes’ chain will skip when it’s worn, but I don’t know what the Schlumpf will do. Probably slip.

That’s definitely not the problem. I torqued the cranks to ensure they are set right.


700 miles. I had 100 miles on my ODO before Vietnam, rode the 300 miles in Vietnam on the old hub (400 ODO). I got the new hub right when I got back, and now my odo is over 1100.

I hadn’t done anything to the hub other than tightening the cranks. It says to grease it 1-2 times a year…and I haven’t had it even 6 months!


It seems like whatever mechanism keeps the axle centered in the hub has failed.

This problem seems different from anyone else’s so far.


Hopefully you guys will post any response you get from Florian. I don’t know if Florian has open or captured bearings in his hub. Open bearings are more subject to these problems. The axial stability of the axle with respect to the hub has to be set by a lip or a retaining ring against the inner race of a bearing. This would be a bearing inside the hub, not the wheel bearings that attach to the frame. When done in a tidy fashion this would be inside the housing and invisible. In my renditions (not a tidy fashion) these are retaining rings outside of the housing and visible. The motion exhibited in your video could arise from a worn bearing in which the inner race could shift axially with respect to the outer race. This would be accompanied by grinding or rumbling of the bearing and that doesn’t seem to be the case. A worn retaining lip on the axle or a broken retaining ring would behave the same way.

Interesting! Maybe this is the problem. I was experiencing some grinding and rumbling noises on yesterdays 10-12 mile ride before I had the freewheel problem. I stopped several times to examine the hub, shift through rotations, and make sure the noises weren’t my spokes or brake rubbing.

FWIW, I’ve also broken 4 spokes with this wheel build (broken at the bend side). My prior non-geared coker wheel I had never broken a spoke.


NOOOO!!! Corbin, that sucks! I was lucky to have broken mine sufficiently early! I’m definitely going to bring my ungeared 36 with me to RTL…

If you ship the hub to Florian UPS Express and he fixes it RIGHT AWAY and ships it back to you UPS Express (he did for me, and says he does all the time for broken hubs) then you can still get it in time. Methinks if you send it now, he’ll get it Monday, and if he ships Monday or Tuesday, you should get it by next Thursday or Friday. There is still hope!

What if you did this? I’m not… advocating a DIY fix, but merely brainstorming. Okay, disclaimer done. What if you tell Florian that you broke your hub, and then ask him if it’s okay if you try to fix it for before RTL? That way, you could clear it with him to get inside and maybe fix what’s wrong, so he’ll still fix it for you after RTL if you’re unable to make it work again. I think that’d be the way to do it… unless you need a replacement part. If you did this and were able to identify, with Florian’s help, the part you need, he could ship it to you and you’d have it by Monday or Tuesday next week… plenty of time to get it all set to go before RTL.

Good luck, Corbin! We (all of us at RTL) need you on your geared hub! (You’ve gotta be the fastest GUni rider I know… it’d totally be a shame if you ended up without your hub at the race!)

wow, Ken. That’s a GREAT way to think about it! So true!

Wow Corbin, that really bites. I’m glad you weren’t hurt!

Man, you bought a really expensive hub to compete in an important race. In my view, Mr. Florian need to replace your hub before RTL, or he can rent a hub to you… :wink:

Bye and good luck!

Well, that isn’t quite true. I bought the hub because I wanted it and it suites my riding style (low cadence, strong legs). I also have had constant problems with bending crank arms, so a splined hub with strong cranks sounded perfect for me.

RTL (and the Vietnam tour, for which I didn’t have the hub in time for) were factors that pushed me over the edge for buying it. So, the race did influence me, but it wasn’t the reason I bought it.

I really love the hub. It really renewed my interest in long-distance unicycling, as I was starting to get bored with it (I like physical challenges, and riding a long distance only challenges your crotch pain).

I’m confident that Florian will stand behind the product and help me get it going. If I don’t get it before the race it won’t be the end of the world. I’ll just end up riding (slower) on Jason (meaestro8’s) coker.


This is one of the biggest disadvantages of buying new technology as there always seems to be problems when products first go on the market. Most things don’t get tested good enough in labs, they actually need real people using the real products to see what problems they might have…Nonetheless, I hope you figure it out and get it fixed as I too want to see the speed machine I’ve heard and read about so much!

You’re welcome to borrow my Hunter. It’s got an airfoil rim, SS spokes, extra wide hub and a wheel TA tire.