Riding Schlumpf hub help

Hi there,
I bought one Schlumpf hub trying to get a little more transit speed on my KH24. I do not know much about this hub and how suppose to work, so, maybe one of you with experience could guide me through it.
Yesterday in installed on my KH24 and today went for a ride. I could not start on high gear, was extremely heavy. On the fly the few times i could manage shifting to high gear was heavy but not that much (inertia help) - it is this normal being that heavy? I’m using a 125 crank, should i use a larger crank?
Also when riding at normal gear i noticed a sort of very light knock, is this normal?

Any other suggestions you guys may have, please feel free to put it here :D.

Many thanks, Juan M>

The knock is normal. There is a little bit of “play” in the system, which you get used to after a while. Not sure what you mean by “heavy” but riding in high gear takes more work. It’s going to feel very different from a regular 24" wheel. Make sure there is no extra friction anywhere, and make sure the bearings are clamped properly.

Enjoy riding it and increasing your speed and shifting skills!

Hi John,
many thanks, yes more work but it seems to me quite a lot. Wheel and everythinmg else rotate freely, maybe i just need to get used to this “more work”.

When shifting i should bring my body little further forward to compensate the initial “jump”? What you do? What about downshifting, what i should expect? :thinking:

Many thanks, Juan M>

125mm is a relatively short crank length for a 36" equivalent wheel; if you don’t have experience riding 36" wheels with that crank length, it will seem difficult. (And it’s harder on a geared 24" than it is on a pure 36").

Yes, you should shift your center of gravity forward when shifting up, and backwards when shifting down.

Tholub has a lot more Schlumpf shifting experience (I don’t have one). For a longer crank, try 140mm or 150mm. 150 will be good in high gear, but may not be fun in low. 140 might be a better compromise.

I use 150mm cranks on my KH24 schlumpf and practiced changing gear first on a very flat, smooth surface which worked very well. I recommend keeping your tire pressure high while you’re getting used to it.

I would strongly recommend dual hole cranks with 150/125mm. Then you can just use the 150mm setting for some real muni riding and maybe later the 125mm for light xc and mild downhills. I have a similar setup with my 26x3 wheel, dual whole cranks and Schlumpf hub.
Actually I rarely ever use the 125mm setting on it because it is much harder to slow down when going downhill in high gear and much more effort for climbing. Of course with a brake the downhill part would be a lot easier, though. But the high gear becomes pretty unusable on anything other than flat or slightly downhill/uphill passages. So basically I think the 150 setting will let you get used to the hub much quicker and will be more versatile for all sorts of terrain.

I think the high gear is quite a bit harder to ride in than riding a 36", also because there is more friction caused by the gears and the fat tire. Of course my geared setup would translate to a 39" - 40" wheel diameter in high gear, so that also explains some of the different feel compared to a 36". Your high gear should be a little more similar to a 36" wheel.

In case you don’t have brakes installed yet I would recommend you to do so. And maybe try a detachable touring handle for the not too technical rides.
I hope that helped, have fun riding!

many thanks for your replies with valuable information. Have any of you tried 137 crank? I’ll go with 150 and then see how it work out. :roll_eyes:

I’d just keep the cranks you have… you’ll get used to them.

The cranks on one of my unicycles are so short that you just kind of rock your ankles to pedal. Riding it feels like coasting.

Riding a geared wheel feels so totally different to the actual wheel size, and still quite different to the effective wheel size. Experience riding a 36" wheel will help, but it’s not going to be the same. It is basically one of those new skills that you have to learn, and practice, practice and practice.

To make it easier to learn, as has already been mentioned, try riding on a smooth level surface. A large indoor gym would be great, but a tennis court or similar will still be good. Riding on a smooth road tyre will be much easier than a knobbly muni tyre (and have them pumped up quite hard).

I find shifting up a lot easier than shifting down (99.9% success vs 75% success), but, again, it comes down to practice. The method I use is to ride slowly in low gear, and pause just for a fraction of a second while the cranks are horizontal and flick the button with my heel. The momentum of the wheel and my body soon gets me moving forward again, but the pedal does have to be pushed a little harder than in low gear otherwise you will just step off of it. Down shifting is similar, but the speed is key, and you have to get the button at just the right moment.

I have heard about some people that push hard in low gear, and click the button without letting up. It will stay in low gear until they ease off with the pressure for a moment, when it then just clicks in to high gear. It isn’t an easy method, and not for everyone, but apparently it works well particularly if you’re in a hurry.


Edit - Oh, and crank size. I’d stick to what you have got and try to get used to it. I have 127mm cranks on my 29" wheel and that does me fine. In fact, I find it much easier to shift with that size of cranks, but this is more to do with the size of your feet than anything.

Like all aspects of unicycling, practice, practice, practice. For the relatively short time I used my KH/Schlumpf hub (currently in Switzerland :frowning: ) I rapidly got used to the quirkiness of this hub in overdrive mode. Before my bearing failed, I was riding a familiar 10 mile road course on my KH24 with 150mm cranks as fast as I was riding it with my 36er with same sized cranks… Of course my ultimate goal is to mix in technical single track with sections of easier fire roads so, for me, this a good set up. Anyhow like Corbin mentioned in another thread, always start out in low gear and force youself to practice riding and shifting into high gear (same applies to going into low gear). The first several “rides” I was just practicing in a large, empty, parking lot just shifting up and down, up and down until I got fairly comfortable. Good luck! I can’t wait to get my upgraded hub back!