KH/Schlumpf issue

Hey guys!

I got me a geared hub a few weeks ago and obviously i LOVE IT! I put it on a nimbus 29" with KH rim and Big Apple tire. I had to modify the bearing holders a bit with a grinder.

Although there are a few things that bother me:

The main thing is that the right crank comes loose sometimes. I’ve now tighten it so much that the crank is scraping against the frame bearing holder.
I heard someone mention something about a spacer, but I didn’t get one with the hub.

The other thing is that I’m having big trouble turning. In low gear it’s fine, but making sharp turns in high gear… I just can’t do it.

And the last thing:
I can’t seem to go that fast yet. Some of you are able to ride comfortably in 32 km/h (20 mph) and i average 20 km/h (11 mph). I hope and think its a matter of time, but do you have some hints on how to speed up a bit?


I had the same issue with my right crank, it came loose quite a lot. I just kept on retightening the bolt, and eventually took a torque wrench to it and applied 25 foot pounds to it. Just make sure that if you do that you are turning it controlled and don’t strip the bolt. Luckily I am not having the same issue as you with the crank scraping against the bearing holder/frame. I am not sure what you can do about that, email Florian or Kris and see if they have a solution. Hopefully Kris will see this thread and give you a response because I am curious as to what can be done in case my crank ever gets pressed on too far and scraps the frame.

I am not averaging 20mph on my geared 29er, but some were saying that they could average 20mph for a while easily on a geared 36. I am not sure how long that has been sustained though.

What size cranks are you using and what type of cranks are you using? I am using the dual drilled KH moment cranks and I have my pedals in the 125mm slot and I find that I can go quite fast with this set up.

As far as turning goes…I have no problem making sharp turns in high gear. Just keep on working on it and lean into the turn.

Also, this might be of interest, but through two separate emails to Florian a while ago, I asked about how much torque I should use when installing the bolt and if I could use Loctite (which I have not dont yet, and if my crank stays attached now which it has been doing recently, I will not use it):

my first question: “I have the KH/Schlumpf muni hub and I was wondering if it would be alright to use Loctite on the ISIS crank bolt? If so, what kind of Loctite should I use? I am considering this because my right crank arm has come loose several times now while riding, and I want to make sure that it would be alright to use Loctite before I actually do it.”

My other question to him was “What is the recommended torque in foot pounds or inch pounds for the crank arm bolts on the KH/Schlumpf muni hub?”


Hope that helps.

yeah 20 mph on a 36 geared. I think i’ve had my 29 up to 20 mph but only as a maximum, not for any length of time.

Turning is just something to get the hang of, it acts kind of like a big wheel but kind of not.

After riding some more, I don’t think 20mph will be a realistic all-conditions flat-ground average for my geared 36. I think the number will be closer to 18.5 or so. Right now, still lacking some confidence (less and less though) my “happy” speed on a smooth without wind seems to be 17.5 or 18, and I’m hoping that’ll increase. I can easily pick it up to 20 and hold it there for a good non-sprinting amount of time, but for an entire long (say, 50-mile) ride, 20 seems a mph or two too fast. Maybe once I shorten my 165 cranks and have a month or two of riding under my belt 20 will become more realistic, but for now, 17.5-18 is where it’s at given the bumpiness of roads and the unpredictability of wind. With a tailwind, 20 is quite easy, but even small deviations from the ideal cost me a big hit in speed. I think I still have some improvement to do, but I’m slowly learning what’s possible for me.

siafirede: Im using dual drilled moments, 125/150. The pedals are at 125 now.
Thanks for the tips, lets hope Kris sees this :slight_smile:

joemarshall: I was hoping that was for 36". I too have reached almost 20 mph, but that was downhill, and I UPD:d doing it (that was fun though, I intuetively rolled, didn’t hurt at all). Not something I could do for a long time…

The thing that bothers me with turning is that when I try to lean sideways the wheel doesnt want to, it just stays vertical. In low gear I can lean as much as the wheel, but whenever in high gear the wheel is straight and I have to bend a lot at the hip.

I think you are experiencing the flywheel effect. As unicyclists, we are all used to the behaviors of a wheel moving at 1:1 ratio, including the knowledge that a 36" wheel tends to be heavy, and harder to move.

Change the ratio to 1.5:1 and increase the speed, and that wheel resists more. Imagine how a rider steers a 350kg motorcycle. You can make instant changes in direction, but not by waiting for the cycle to lean over. You have to force the issue. On the motorcycle, this is easy to do by pushing forward on the handlebar on the side toward which you want to turn. Want to turn right? Push on the right handlebar. Sounds counter-intuitive? That may be why it’s called counter-steering. That push makes the front wheel go left, which causes the cycle to lean over to the right. It’s actually very easy to do.

On a unicycle, you have to twist at the hip to start the process. Want to turn right? twist the wheel a bit to the left. Instant lean. This is a key skill in making fast times through the IUF Obstacle Course (race). On a Coker you’ll want to learn the skill bit by bit. Stick with it!

Sorry to thread jack, but I’ve been debating whether to go with a geared 29er or 36er. I like the feeling of being over 6 feet tall on a coker, but I also like the portability and climbing ability of a 29er. It seems logical to me that if speeds greater than 20 mph are possible on a geared 36 with 165mm cranks, then those speeds could also be achieved on a geared 29 with 125s. Has anyone had experience on both a geared 36er and 29er that could help answer this question? -Jason

I have hit 20mph on a geared 29 with 125s. It’s comparable in speed to a geared 36er with 152s; perhaps a smidge slower.

One nice advantage of the 29er; in traffic, you can pop it down into low gear to easily idle at a stop light.

I can attest to John’s expertise in this area, having witnessed his impressive performance in the event at NAUCC2007. Bravo, John, not only for the smooth run, but for all the encouragement and assistance you provided to the younger competitors. I only wish I had recorded it.

Well, I’ve tried the counter-stereing for a bit now and it really works!
Thanks a lot johnfoss!!

It doesnt work perfectly yet, but I realize that I just need more training.