Schlumpf hubs: general discussion

You misunderstand (or I misunderstand you) - I’m not suggesting having a crank stop in the way shown in that figure - clearly the bearing couldn’t get past the stop machined into the spindle (and in any case we’re talking about doing something with a Schlumpf, so no modifying of the spindle allowed). I’m simply using it to illustrate the position of the end of the splines relative to the stop.

Yes, I know what you are suggesting. I brought this idea to the forum a while back, it’d work if someone can do the machining. It would probably be easier to make a compression style bearing spacer that goes on the smooth portion of the spindle.

Either way, this is going to be retro as I am nearly certain that the next gen hub will have a different spindle to accomodate for crank creep.

If some enterprising individual were to make a spacer that prevented crank creep, I am sure they could recover their costs, $50 a set, sell 100 sets, that ought to cover it.

I think better with pictures. Is this the kind of thing you are suggesting? (Item in green.)

Schlumpf w_crank spacer1.JPG

Schlumpf w_crank spacer2.JPG

that would do it… no crank pressure on the outside of the bearings

Nice picture, that’s the ticket!

It might require some machining at the cranks too.

I was working with a machine shop a few years ago and a welder took me ona tour, they had some very high end pieces of equipment, one was a “punch” that used a super heated piece of metal to put shaped holes in metal blocks, so maybe one of those with the correct ISIS plug?

Of course CNC would be easy enough, just need the correct steel or Al discs; I’d use stainless steel, harder than al, last forever.

sorry yes there was no ref to geared hub from Kris…
Kris was saying KH unis come with spacers between the crank arm and bearing itself.
“Without disc brakes you can get away without them but for precise disc brake installation they really are needed”
Regardless of Hub being a moment, Schlumpf or other, if we run Spirit cranks why wouldnt we run these spacers here as pictured?
Isis crank spacers can be bought from UDC in 3 widths. Cant go wrong really. Works a treat and only need one on the disc side really.
Crank arm still has plenty of bite on the axle spline also

The issue is that on Moment hubs or any other standard hub, the bearing is supported with spacers on both side of the bearing. So there is no net lateral pressure on the bearing from the spacer. On the KH/Schlumpf hub, you can’t see the inside of the bearing but that’s not the case. So pressure on the outside puts lateral pressure on the bearing itself and causes bearing wear.


Any chance you’d be willing to make a retro “crank stop”?

Also, the big question: What will change and when will the new hubs be available?

Thanks for chiming in on the use of standrd ISIS spacers.

I really can’t make a retro crank stop as the “official” brand on the hub because there’s no way I’d be able to guarantee it. Sorry about that. All I can officially recommend is for riders not to use a spacer or if they do, to realize it is at their own risk. And that it’s really easiest to use rim brakes. On the positive side, it is true that of all rim brake setups, the geared hub does work relatively the best in that the large flanges make for such an incredibly stiff wheel.
Re ongoing hub developments. Also, sorry I just don’t know yet except to say that for sure it won’t be in the next few months.

Yes, I’ve found that to be a great benefit in that my wheel has remained perfectly true since it was built more than 2 years ago, and after more than 1,000 miles of pretty intense riding! :slight_smile:

Since we’re at 1264 posts at this point it might be worth noting again:

If you DO want to try the disc setup: Install the cranks with 30 Nm torque after applying blue loctite. Leave the cranks on the hub and don’t switch them. There may be some grinding involved initially to the disc mount on the frame and adapter for the caliper to make the setup work. Since this is under the officially recommended installation torque, check the bolts more frequently than if following the owner’s manual instructions.

Rim brakes: higher installation torque- 40-50 Nm. Loctite still applies.

Rim brakes are much easier to set up for those who are less mechanically inclined. Also, they do have the added advantage of taking the load off of the transmission when braking. This can be a distinct advantage in making a shift when the transmission is under load as internally geared hubs inherently don’t like to shift under load.

In a disc brake system the disc transmits all the force through the gearing system when braking and shifts can be a bit more sluggish if braking and shifting occur simultaneously.

Regardless of which system of brakes are chosen, a Schlumpf is quite a piece of engineering that isn’t for everybody. But for those who like it- it’s really worth it.

And waiting for the next generation of hub just means you’re getting older and losing days that could be spent riding your Schlumpf.

Well said!

Thank you for touching on lateral pressure of the bearing on the Schlumpf. Hard to tell without seeing the internals.

After many miles running an isis spacer here i have had no issues to date (touch wood)

I havent checked but i was under the immpression my crank pressure on this added isis spacer lay flat against a circlip on the Hub axle?

My reason for running this is even at recommended torque and ground back bearing cup, frame cup and disc bolts, tolerances were still tight on one of my frames. Another is was fine.
For muni i like 1mm or so for dirt and grit to clear so it does now grind and stick as bad to the Geared Hub seal.

I will for now hold my trust in the bearing from suffering excessive wear and continue to rack up the distances.

Rim brakes for Muni , dust, dirt, mud, h2o and longer descents i like my overside disc when Gunning

Thanks for all the precise info forwarded here

Crank stops on a Schlumpf hub

I hesitate to add much more to this discussion, but I was thinking about this subject today, and went back to review the data. Here some items to consider:
– The ISIS spec calls out for a hard stop to be incorporated into the drive spindle, between 16 and 16.5mm from the end. This is also the spot where the splines are supposed to end (the flat region of the sline ends 3mm before that, and the rest is taken up by the tool radius).
– The Schlumpf hub (the one that I have, anyway) does not have this hard stop. (I’m guessing something about the hub design precluded this feature.)
– What the hub does have is this: the end of the spline is about 17.5mm from the end of the shaft, and the snap ring that retains the bearing is about 1.2mm beyond that.
So I’m guessing (emphasis on the word guess) that the designer decided that since he couldn’t include a hard stop, that he would instead locate the spline end and snap ring far enough from the end of the axle that the crank would stop from the ever-increasing resistive force of the 1 degree included angle, and not be able to come in contact with the snap ring.
However, the crank side of the ISIS spec calls out for a 3mm space from the end of the crank splines to the inner surface of the crank body. So unless the 1 degree taper offers enough interference to bring the crank to a stop before it hits the snap ring, it seems that there will be contact in some cases.
There are two possible solutions that I see to this. One is the aforementioned crank stop which fits into the splines. (I made an illustration of this earlier.) I don’t see this as ideal, since the radiused ends of the spline channels were not designed for this type of fit. Still, I think it’s a viable solution, and would work.
Second, if tightening the crank brings it up into contact with the snap ring, then grind or mill the back surface of the crank until it clears. Personally, I like this approach better. Not all cranks are the same, some will probably clear without any issues, while others may not.
I suggest as an addition to this thread that people post their experience with specific cranks. I’m still in the early stages of my particular build (making the adapter rings for a 48 spoke/32" wheel, also illustrated earlier), but when I do get to the point of selecting and fitting cranks, I will post my observations.

Broken bearing in Schlumpf!

Hello everyone!

So, yeah… One bearing broke in my hub, I’m pretty sure I know which one is it. The real question is, I sent an email to Florian a few weeks ago and still didn’t get an answer. Is he still active? Has anyone gotten news from him recently?

I am currently wondering if I should do it myself. I have aaaalllll the tools at work and at school to do a professional job. I can also get any size of bearings. I’m just worried for the warranty, I know it will vois the warranty but it would probably end up waayyy cheaper. I am the type of guy who could end up reparing schlumpfs…

It took about a month to get a reply from him when I e-mailed about my broken flange, but he did eventually reply telling me to send it in (checking back in the thread, that was about 7 months ago).

If you can repair it for less than $150 I would go for it. Sending my hub in for warranty work I could have done myself was one of my biggest schlumpf related regrets. Sending you hub in for repairs also has a sneaky tendency to make you buy a second hub while your first of relaxing at the spa, this will ultimately cost you even more than the initial $150 shipping.

Hearing this make me sick. I can understand the difficulty in manufacturing the hub - it is the outstanding and unique product. I can even accept quality issues. What I can not accept is these delays which, in my opinion, show the disrespect to the customers. My hub has been working nicely so far, but I am not sure I will order another one some day.

Well, after talking to a few friends about my situation, I decided to do it myself. I will be filming the whole process to make sure I put it back together properly. I’m not riding my Schlumpf in the snow so I have until March to do this. I’ll start during my holiday break.

I will tell you guys how it works out!

Hi all,
I’m sorry to disagree with saskatchewanian and FatBird (ps: Eric and Leon, I’m Nicola, from italy)…
Two years ago something broke inside my hub. I made a video and I sent the link to Florian.
Here’s the video:

Well, after seeing the video he said me that it was their fault and they sent me a shiny new hub, for free, in a couple of weeks!

This year I had another little problem: the external shields were moving.
At the beginning his email answer was slow (so I simply sent a new one :slight_smile: , but then Florian answered me soon, and he sent me their official glue, the instructions on how to glue them, and also this time for free!