Schlumpf learning journal

Yesterday my Schlumpf wheel and frame arrived from Germany. The other parts I took from my 24 Muni.

Rim: 26 inch KH freeride, with the stupid holes.
Tires: Schwalbe Mudy Mary, 26x2.5. It is 67! mm wide on the KH rim. Weight 1 kg, and HUGE rolling resistance, great for leg training :roll_eyes:
Frame: KH
Cranks: KH moment 125/150
Saddle: KH freeride, with T-bar.
Brake: Magura HS33.

Today was the big day, the first ride on my new toy:):slight_smile:
The plan is to first get familiar with freemounting in high gear and riding in high gear. Shifting on the fly I will practice later, on a soft surface, not tarmac!

I first practiced riding of, from the wall in the backyard, just like my uni learning days three years ago :sunglasses:
It didn’t took long before I could ride of, maybe 10 minutes.
Freemounting in high gear also didn’t take long to master, maybe another ten minutes.
I was ready for an evening ride around in the neighborhood, so I took my baby for a few km’s ride on smooth tarmac.

First few hunderd meters were a bit of a struggle, but then the ride became smoother and faster, I even overtook a slow cyclist:)
I think I am in love with the uni :o

A few things I noticed, apart from the speed of course:

  1. I really don’t want to UPD on full speed. :astonished:
  2. The pedalling feels really heavy, it feels more like a 1:2 gearing. Maybe its the big slow rolling tire, maybe the hub efficiency? I am not going to change the tire yet, I need some good leg training.
  3. The high speed gives a good straight line stability.

Some things I did NOT notice.

  1. The hub does have some slop, but I did not notice it while riding.
  2. I did not notice the forward pulling of the frame that some people mentioned.

After a few km’s I dismounted and shifted to low gear. Now that feld really awkward, my balance was completely of.

I will keep you updated on my next ride.
This weekend I will try to ride some easy forest road in high gear.

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Freemounting in high is really tough
Good for you for getting it though

I had similar plans as you when I got my hub. I planned to get used to high gear. Then worry about shoring later

Had the hub 1 year now and I still cant start in high
To be fair I don’t feel the need to

I think learning to shift on the fly is much easier than starting off in high

Just for reference my set up
Exactly the same as yours
Only difference is tyre

I went in the other direction. I started with maxis hookworm. As I planned learning to shift on Tarmac

The key to leArning shifting for me was shoes. With my normal shoes I was trying ankle shifting and I smashed myself to bits
Once I got my 5:10 karvers (the ankle bone protection is great) I got much better much faster

Have fun. I found learning to shift and ride in high as much fun and as sattisfying as learning to ride to begin with

Just curious why you went with such a heavy tire? (about 3 pounds according to this site) (same here just to make sure)

What a timely thread for me - I’ll just sign in here. Got my first guni on Sunday, and due to illness today was my first proper attempt to ride it. Is a secondhand (well actually third hand at least - I missed out on it the last time it was for sale, but have now bought it from the chap who beat me to it) original Schlumpf hub on a Schlumpf telescopic frame. Built up as a fast lightweight road 29er with a Mavic TN719 rim and a Schwalbe Marathon Supreme tyre, 150 cranks. Suits my original intended use of a guni perfectly, but I’m going to be so tempted to at the least try a knobbly tyre at some point (I guess given the square taper axle I should resist rebuilding onto a wide rim, as that will only make me tempted to do stuff which risks damaging it).

Only got 10 or 15 minutes of playing around whilst “looking after” my kids who were busy playing on jumps with their bikes, so only up and down our little bit of road, but did succeed in freemounting and riding a bit in high gear. No shifts as yet. Found mounting onto the wheel in high gear remarkably easy, as with a tiny bit of forward momentum you can pretty much just step up on the back pedal - though getting going is still kind of interesting, and when I did the speed picked up scarily quickly for the small space I had (and complete lack of protective kit :o ) Will have to go for the full set of kit tomorrow - including the knee and elbow pads I own but have never worn on a uni - and head out to the nice flat straight bike path and see what I can do. Given comments about footwear and shifting I guess I should also dig out my Shimano AM41s - I usually wear Vans Gravels except when it’s wet and/or cold, but those are low cut and the AM41s have a high ankle in the inside.

you seem to be progressing a lot quicker than i have heard it takes most people.

I got a 26" guni a year ago. I have never tried to start in high gear, but started to practice shifting right away. It didn’t take very long before I could shift up - down was a bit trickier. However, it took quite some time before I was comfortable and enjoying myself in high gear, so stick with it Twente. :slight_smile:

I make it a point to rarely start out in high-gear so I can practice the upshift. However, on occasion I’ll start in high gear if I had a UPD in high gear riding down hill. The downhill highgear mount is then so much easier to get going.

Regarding shifting in general; helps to have shoes with a more firm or hard heel that makes better contact with the shift buttons. Soft soled shoes make shifting much more difficult! Another thing I’ve learned being someone with small feet, going to a shorter crank size really improved my shifting (up and down) percentages. With the 150mm on my 24" uni shifting was doable but not so automatic, with 137mm cranks I can shift on the fly very rapidly. Something to consider.

I’m about to re-learn how to ride my KH-Schlumpf hub soon as I’m right now building up my new KH 26"! Should be a fun challenge!

I have the lighter freeride version, that is 2.2 pounds.
I choose this one because it is the biggest tire under 1 kg.
Plus it has great grip in almost all conditions.

All of you, thanks for the shifting tips.

Right now shifting feels scary, I don’t want to break my tailbone;)

I still have the the wrong shoes, no ankle protection, and soft soles.

I do have footballers shin protectors, which have ankle protection also.
I took out the inside ankle protection, for unplanned shifting.
Maybe I should put them back in when I start my shifting practice.

Some people find freemounting in high gear difficult, but actually it is easier then free mounting a 36er.

The weather was pretty grotty today, so I never made it to the bike path I was planning on riding, but I did have a bit more practice outside my house and also took the Schlumpf to pick up my son from school - which includes a reasonable length of straight bike track. Managed to freemount in high a few more times, probably getting on for 50% success rate.

So I then decided to try shifting - at which point I had a problem, as mine is an original square taper Schlumpf which has the original Schlumpf crank arms. For some crazy reason the Schlumpf cranks have an outwards bulge in the middle (as can be seen at ). This meant that when I tried shifting my feet kept hitting the bulge and not the button - in order to be able to reach the button I not only had to move my feet back on the pedals, but also outwards to give me the angle to reach past the bulge - what a stupid design for cranks to use with a Schlumpf! Fortunately the chap who sold me the guni also included a spare set of straight crankarms, so I reckon they’re going on tomorrow.

Despite all that I did manage a few upshifts without UPD. Including at the start of the section of bikepath on the way to school (I’d ridden the rest in low so as not to make it too difficult). Being slightly downhill it was so easy to pick up speed, and actually a bit scary - am going to have to work on getting comfortable with the new balance envelope. I shouldn’t be surprised at how much of a challenge it is, as effectively I’m riding a wheel 50% bigger than I’m used to (have never ridden a 36er), and I do remember my 26er being tricky at first coming from a 20" beginners uni.


How were your first shifts, did you have nasty falls, or only UPD’s ?

Ride two

I have just returned from my second ride in high gear, I did 11 km on smooth tarmac. I am getting a little more relaxed now, my cruising speed is between 18 and 20 km/h. I am starting to notice the gear slop now, but it is not really annoying.

At the end of the ride I changed to first gear (not on the fly), and I couldn’t freemount and take of :thinking: . The feel in low gear is so different, my mind cannot deal with this sudden change at the moment, I hope practice will improve that. It takes some minutes to get comfortable in low gear again.

After the ride I practiced shifting next to a wall, inside the garage.
Shifting up, the cranks rotate about 20° before engaging second gear, is this normal?

I also discovered that I really need new shoes, or I will hurt my ankles.

I have the feeling that the big tire is really slowing me down an tarmac.
I hope it shows its good qualities in the mud this weekend, it has rained a lot here last weeks.
But I think that I cannot resist to try the Schwalbe Furious Fred 26x2.25 tire I have on my MTB. A 400 gram tire with low rolling resistance.
Yes, I like to experiment with tires, like some other forum members:)

Only UPDs, but I’m still yet to get any speed up on this uni, and going really slow when trying to shift.

I tried to change my cranks before riding today, but found the spare set wouldn’t go on without interfering with the bearing holders, so for now I’m stuck with the Schlumpf cranks with a bend in. So I played around a bit with foot position and found that with my feet a little back from what I’d like I can hit the buttons with my heel, with the instep going around the bend in the crank. Would still like to get some slightly shorter cranks, 137 or 140 ideally as I don’t think I want to go down to the 125s I have on my 29er unguni, but these seem few and far between in ST, and I’ve now discovered the problems I’m going to have with getting a set to fit.

Unfortunately I still really wasn’t getting the changes with my Vans Gravels - tried kicking the button, but can’t yet get the timing and sliding the shoe down the button doesn’t seem to work. So back to the AM41s - will have to have warmer feet, though winter is coming so that’s not such a bad thing and hopefully by spring I might have sussed shifting. Those are high tops (on the inside), so I should be able to change with my ankle, but in fact it was working with those sliding the edge of the shoe over the button - it seems the outside of the shoe is a slightly different angle to the Gravels which helps here. Managed several successful upshifts and eventually an upshift followed by a downshift. Generally managing to change without UPD now provided I don’t have to work too hard to get the button press - though I need to get out somewhere I can use the speed and try going faster.

Yes. The hub has pins in it and when you shift it needs to rotate to the next position to be engaged. Also, it won’t disengage until you let up some on the pedals, so if you keep pressure on the pedals it can take a a while until it actually shifts. I’ve consistently had it where it’s taken a couple revolutions before a shift actually happens after the button is pushed, a problem I have on my isis schlumpf and not on my old square taper schlumpf.

Thanks all for documenting your experiences. I’d like to contribute mine. I don’t want to sound arrogant, so please don’t take it that way. After reading people’s difficulties I was extremely nervous about the learning curve. My perspective is to hopefully encourage others who read this.

I just got a 36 Schlumpf (Hunter) a few days ago. Due to some technical difficulties I didn’t get a chance to ride it until a couple of days ago. To say that I was nervous about shifting and falling was an understatement.

I rode it to work in 1:1. On the way home I figured I’d try high gear. The first time I shifted (standing still) and tried to ride I didn’t get more than a revolution of the cranks before falling off. Falling isn’t the right word- more like stepping off. After a few more tries I could ride a few pedal strokes in a straight line. I needed to head home so I rode 1:1 for a bit then found a utility pole I could hold on to and ride away from on a low traffic street.

After a couple of tries I got high gear starts to work, but was still struggling with turning and general control.

I went home, took a short nap, and headed to a low traffic neighborhood (with off street parking should things go awry) to give shifting a try. I was pretty freaked out, but determined to get it. The first time I hit the button and got it to shift (after a few tries) I stepped off the back when it shifted into high. A few more tries (5.10 Impact 2 shoes, size 12, and 137 cranks) and I could get it to shift into high while riding without falling off. I was getting the high gear riding under control too.

Then I came to a rise and needed to downshift.

The downshift was making more nervous than the upshift as I was thinking I could easily taste tarmac by flying off the front. Surprisingly, this wasn’t the case. Of course I wasn’t moving fast, but I was moving.

I kept practicing (looking at the buttons to make sure I had actually shifted) for a bit and was getting OK at shifting on the fly. A bit more practice and I was able to shift without looking at the buttons and on slight up and down grades.

High gear was becoming much more intuitive as well. The bit of backlash is still a bit weird, but control is becoming normal. I didn’t have a speedometer on, but from thousands of miles of ungeared experience I’d guess I was in the 15-18mph range in high gear.

Once I got used to the bit of backlash and shifting, the weirdest thing I experienced was the funkiness that occurs when my legs have to adjust my balance from pedaling high gear to pedaling low gear. It is really a weird experience.

I did UPD a few times, but never was it more than just stepping off the back of the uni when shifting gears and I lost my balance when the cranks were moving to lock into position in the other gear. I never totally bailed.

Within an hour of starting I got somewhat proficient at riding the Schlumpf and shifting on the fly. I tend to think that the 36 will be the hardest to learn due to 1.5 x 36" being > 1.5 x a smaller wheel.

I think the Schlumpf would be a total blast in a 26" Muni.

Once again, I’m not trying to be arrogant. Hopefully those who are reading and thinking about a Schlumpf aren’t completely scared as I was.


Your experience is not very different from mine. I did not find shifting all that hard to pick up when I was starting out. However, I still cannot shift on demand every time or in only one rotation. I have been riding on the road and so do not shift all that often in a normal ride.

I find proficiency with high gear to be more challenging than shifting with a 36". I can ride it fine, but the balance envelope is much narrower than a normal 36" and I had a number of falls, some not pleasant, early on. I have since backed off and have been riding it with the goal to be as comfortable as possible rather than pushing it. That attitude has worked better and I am riding more easily with very few UPDs.

Good luck with your new toy. It is a lot of fun and a new challenge.


The question then is whether the balance envelope is smaller than the envelope would be for a 54" wheel, ie is it the Schlumpf which makes a difference or is it just that a bigger wheel is harder? In other words does a Schlumpf 24 have a smaller balance envelope than a 36 unguni? Just wondering whether it’s some added factor with the Schlumpf which makes it harder to ride - plausible, as the action of the torque arm on the frame could provide positive feedback.

I went out for my first proper ride at speed today. Went out with the intention of getting comfortable rather than pushing it - was actually surprised at how fast I did go, with my fastest 500m covered in 1:25.5 (average 21.1km/h, 13.1mph), which included slowing down to pass a group of people - my Garmin says I peaked at 25.6km/h which seems plausible and certainly doesn’t look like a glitch. Wasn’t actually expecting to be any faster than my previous ungeared 29er. Maybe not all that fast - I’m sure people go faster than that on ungeared 29ers, let alone 36ers, but it was my first ride on it at speed, and my previous fastest 500m (on the same track) was 1:35, so that’s the fastest I’ve ever been on a uni. Only had 1 UPD apart from when shifting, and that was fortunately when going really slowly - though actually it seems to get more stable at speed. Had a pretty scary moment at speed once though when I found myself falling forwards and as I accelerated to stay on I realised that if I did come off I was making it worse by doing that!

As for the shifting, that’s getting more comfortable, towards the end of my session I was consistently shifting up and down without UPD - in fact the only UPD I had after my first few attempts was when I tried to downshift when going too fast and my legs couldn’t accelerate quickly enough. Not that I was always shifting when I wanted to - that’s still going to take a bit of practice, but I think I know what I’m trying to do now. I do actually mostly seem to be shifting with my ankle bones, not my heels - helped by my right ankle bone being very prominent, and it is after all the upshift which is more important (at this point for me I’m not so bothered if I have to dismount to downshift). Means I need to wear the AM41s, but hopefully I’ll be picking up some ankle protection tomorrow which will allow me to use the Gravels with that technique.

Oh - I also raised my saddle a bit - had deliberately set it low, more towards my muni height in the theory I had better control that way, but raising it actually made it more comfortable. Up a bit more tomorrow I think. The only issue then is that the 152 cranks definitely feel too long for road use. I’d really like some 140s, but they appear to be like rocking horse poo in square taper, so I guess I might have to try 125s - the same size as on my 29er unguni and they work fine on that, but I was kind of hoping for a lower bottom gear to help me get up the one steep bit of hill I can’t make on that. I just hope I can get some which will fit on the short Schlumpf axle without hitting the bearing holders (the spare 152 cranks I got with the uni don’t).

Third Guni ride today

Today I went for a ride, first time in the daylight, and in the forest.
The first part was a single track, I did in low gear.
them I came to a tarmac bicycle path, I got of and switch to high gear.
A few km’s tarmac and then onto easy forest road, still in high gear.
There I tried my first real shift, slowed down, left ankle inward, and CLICK, I was in low gear :). No UPD, no hassle whatsoever. Also no problem anymore of adapting to the 1:1 gear ratio.
The trail I choose today was very easy, and I practiced shifting a lot today. Shifted up and down about 100 times, with only a few UPD’s.
I find downshifting easier then upshifting.
Downshifting happens mostly in one try, upshifting requires two or three tries.
I experienced all the shifting issues that a lot of people write, like the “gap” between low and high gear, and the shifting delay when there is force on the pedals.
No of these issues throw me of, luckily.

I didn’t expect to shift today, so I was very pleased to say the least.
I expected a far longer learning period.

I see that Aracer is also doing pretty well after just a week, keep going:D

The speed that I get in high gear is about 20 km/h, not that fast, but that will increase with practice.

After I got home I changed the big, heavy rolling tire, for a Schwalbe Furious Fred, the other end of the MTB tire spectrum.
400 gr light, no rolling resistance and no grip.
In low gear the Muddy Mary works fine, but in high gear I constantly have the feeling that it holds me down. Lets see how the FF works out next ride.

You’re also on a smaller wheel than me, with a draggy tyre - I bet you’ll go faster with the Furious Fred (though personally that’s too flimsy a tyre for me even on a bike). Given I had to slow down a bit for pedestrians on my speed runs yesterday I checked through my data to find a bit where I didn’t have that issue, and my largest distance in any 30s interval was 189m, which translates to 22.7km/h or 14.1mph :slight_smile:

Not been out on the guni today - I had an orienteering event and then went for a muni ride in the forest where that was. I don’t suppose it will do any harm to have a break from the gears and do some different riding - I’ve certainly found before that all uni riding tends to help with progress. Did buy my ankle protectors, so hopefully I can go back to ankle shifting using my preferred Gravels. Also had a revelation on how to get some cranks the right length…

An update on my progress - went on a longish road ride from home yesterday and the day before, working on using high gear in trickier situations (my routes from home are far from straightforward, involving steep hills, narrow paths and rough/slippery surfaces), so lots of UPDs! Definitely starting to feel a bit more comfortable on it though - and with the 152 cranks in low gear I even made it up the short steep climb on the way home which I’ve never managed on my unguni 29er which has 125s. Gradually getting the hang of changes, but frustratingly not able to change gear on demand, which means I didn’t use high gear for all the bits I could and stayed in it for some bits where low gear would have been more appropriate.

However when I got home yesterday I went out again with the aim of trying to sort out the gear changes. With a slight change of foot position I was pretty much able to change gear on demand! Tried another little trip around today and seem to have mostly sussed it, am now able to change gear at higher speed which should help a lot. The foot position I need to change gear is still a little further back than I’d like (I have diddy size 7 UK, 8 US, 41 EU feet) - I reckon some slightly shorter 140 cranks should make all the difference and also help my spin a bit, hopefully without affecting my control too much (still a bit nervous at this stage about the idea of putting 125s on). Just need to get hold of some now…

Oh and fastest 500m now 1:17.6 (average 23.2km/h, 14.4mph).