Schlumpf 2022 Build Questions

Never thought about the rod twist. Good to know that’s a risk with overly proud buttons.

Great to know it’s correct and known.

But yes I always check my buttons have a bit of push inwards when engaged. Good way to check if the cranks are loosening.

Shifting with confidence on my G24 makes me so happy. Now to get this going more on the 29er and later 36” :flushed:

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The bigger, the easier! :smiley:
I find the stability of the 36er helps to stay balanced when shifting. Whereas it’s a bit more challenging on the 29er. But once you got it, it will feel natural!

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Got to give this a try - I’ve religiously positioned the buttons so that the flat/back edge is flush with the crank outer surface, but when attempting to shift it feels like I’m often just bashing the side of the button and bouncing off, so failing to shift. How much further in have you tried?

Is this simply due to the button not being able to be pushed far enough inwards from the outside, or can it hit some obstruction in the hub itself that stops it going further in? I guess different crank designs require different positions for the buttons along the shifting rod due to the thickness of the crank at the axle, and a thin crank design could mean the button ‘bottoms out’ somehow.

I feel like my buttons take more effort to change by hand than I would expect, but I’ve got nothing to compare them with as I have only got experience of my own (400 series) hub. Is there a way we could measure the pressure needed for a given hub when pressing the button? And would there be anything that could be done to reduce that pressure anyway?
I guess we could either measure pushing pressure or pulling pressure from the other side, but I don’t know how to do either. I tried using my electronic kitchen scales upside down to press down on the button from above and note the ‘weight’ recorded just before the button shifted, but that was difficult to observe and can’t be very accurate!

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Engaged with room for push in.

1:1 engaged. How far gold protrudes

I think it is more that the shifting process / action, requires the button-rod to go in further than the position at which it rests after a shift. So the action needs the space for the rod to spring inwards - change happens and then button pops out slightly in engaged position. I also suspect it is to mitigate any issues with cranks getting loose and pressing-pushing to button off the rod.

I think there’s a bit of variation for taste and crank depth but the squish of the bottom must be maintained and for me is help to reassure me the axle bolts / cranks aren’t loose and working their way of the axle.

Hope making this adjustment helps with shifting.

No idea how to measure the pressure used and in someways it doesn’t matter - the main thing is that the heel slides on the button’s curve and pushing the rod inwards by doing this.

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Just checking, is the top picture of the un-pressed button, or once it’s pressed in? It seems a long way in already if the former. The second picture looks about like I already have my un-pressed buttons

I’ve edited the above post under the images to be clearer. But yes. First is engaged. Second bottom out ready for a shift. (Top picture isn’t showing a disengage button)

These new hubs do have longer axle parts so it could be helping here.

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Ah well, I suspect I don’t have much adjustment leeway after all, but I’ll give it a try. Thanks for the detail.
I’m wondering if making the outer button surface a bit more slippery might also help for ensuring the passing heel pressure is transferred to go down the axle and not just knocking the button downwards/backwards. But it seems I may be clutching at straws here!

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In the past I’ve toyed with the idea of making something hard and raised as a surface that could be Velcro’ed to one’s ankle or the like. This might help make any button bash attempt to transfer energy more like a button slide.

Hope it works out, John!

Finally got around to trying this out. Swapped the 125mm cranks I had previously installed for 138mm cranks.

The install went well. I used the DIY tightening bolt to pull the crank in, then torqued to 45Nm. Then I backed out the DIY bolt, threaded in the Schlumpf axle bolt, and retorqued to 45 Nm. No deformation observed in either the DIY bolt or the Schlumpf bolt on either crank install.

Interestingly, the shifter rod doesn’t seem to interfer with the hex key on the DIY bolt. I think the washer adds enough space to it clear. There was still some interference when I torqued in the Schlumpf axle bolt, so I took care to push in the shifting rod slightly with when installing it.

When putting the new set of cranks on I also installed 2.5mm of crank spacers on both sides. It doesn’t sound like there’s any issues with using these as long as the pressure ring is also included.


I’ve noticed three things with my new schulmpf and braking.

  1. I only have 100km on my G36 on the road in good weather, but already see this much pad wear:

  2. Braking power is really poor. It is my first G36 and first SRAM brake though… but I am guessing it is a combination of:
    a) SRAM
    b) not bedding in the pads/rotor
    c) G36 weight/wheel size
    d) rotor material

  3. The rotor seems very weak (material-wise). When I adjust my rotor to run straight and not rub, it bends way more easily than other rotors I have used in the past.


Thanks for sharing this.

I am not as close to the issues Becky reported before, but I have been getting BrakeStuff to make two prototype rotors to fit the new schlumpf hubs - one is going to be used by Becky and the other I’ll test - these have been made and in possession so we should get some idea how good / bad they are soon :soon::smiley:

Again I don’t want to speak on behalf of someone else - however I do understand this project from my conversations with BrakeStuff.

  1. Firstly their rotors are made using heat treated steel that is focused on disc rotor usage - whereas Florian’s rotors aren’t heat treated.

1.4301 is the DIN designation for the one we use the most. This CANNOT be heat treated or hardened.

  1. It was advised that the holes could / should be smaller on the rotating edge as this is better for organic pads

  2. The symmetrical design means that when the metal heats up it causes a “dishing” (bowl effect) to the rotor. This means the rotor pulls inwards and when it cools it fixes like that. The standard swooped asymmetrical design of rotors allows the metal to expand with the outside diameter moving naturally outwards - so this is what we’re aiming to get BrakeStuff to make and possible Schlumpf Innovations to adjust to down the line. (This area was relayed to me via Becky as she was able to collect rotor and speak with BrakeStuff in person :pray:)

I’m hoping the BrakeStuff rotors that are already made will be a massive improvement solely due to the metal used - before the design is moved to asymmetrical from a direct copy of the Schlumpf symmetrical one.

The ideal would be an asymmetrical design with smaller holes at the edge of the rotor - but to start with the test is to see how a BrakeStuff manufactured one holds up.


@mindbalance Thanks to you! it’s very interesting!

As for me, I still haven’t built my G36. I had planned to mount the new hub on a 36" carbin rim, but the problems with the disc disc disc discouraged me. As a result, I’m thinking of building the new schlumpf hub with a 29" rim… and building my old n°134 hub with my 36" rim. This old hub have a great history: (Toulouse en Monocycle - YouTube, 10k WR and now a crossing of the Pyrenees)

Thanks for the BrakeStuff lead, I’m very interested :slight_smile:


Thanks for the info! Any news for the 220mm rotors? Do BrakeStuff plan to make them when the 203mm rotors are completely tested? :smiley:

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I can see the logic of doing this. Just a shame in some regards as the 32h new hubs seem destined for a Braus rim.

I’ve toyed with moving my 200series hub to a build like that with the Braus rim - and given the history of your hub it is worth reminding ourselves how good even the old ones are in terms of longevity and ability.

I love that video. Watched that way back when I first learned to ride. Never thinking I’d get interesting in geared riding :gear: Nice to see you taking its cogs to further adventures!

I personally feel less worried about the options re brakes working now that we know we have a friendly company like BrakeStuff able to make rotors to fit the needs more precisely….

And to your point - basically yes: I would have in some ways personally preferred cutting out this first stage test but he seems amenable to making asymmetrical 203 and 220 rotors. I guess it would be a bigger time investment for him design wise so wants us to first see how his rotors generally perform - then we’ll get the design adjusted.

So it’s test - and then scope out designs for a more bike like rotor shape (swoop) and 220 is a must for me and others I think. (100mm, 32h, Braus :grin:)

@Maxence - Is your Braus wheel running alright as of now since the brake switch?

Thanks for the complete answer! I’ll have to be patient, then :frowning:

Regarding my Braus wheel: I wouldn’t say it’s running alright. It’s running, but one or two spokes continue to hit the caliper at some point. I have still not found the ones. It’s quite hard to determine as they don’t hit the caliper when the wheel turns unloaded. I have to be on the uni for the spokes to hit the caliper. BTW, as the disc is not very true, it rubs against the pads. I guess it won’t take long for my pads and my disc to be dead :upside_down_face:
That’s why I’m really interested in BrakeStuff new rotor :eyes:

My plan was to go for a 200 km ride on next week-end with my G36, but I’m not sure I want to try it on such a long distance. I may use my 29er. I’ll have to think about it and try and find solutions before then if I want to use my G36. :thinking:

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Mmm me too - I will see if I can phase up a tactful message to ask if a 220 rotor can be designed now as it is clearly a different animal in terms of testing.

Sorry to ask more questions re your set up:

Do you have any more outward movement of the caliper on its mount?

I know these hubs only have one set of spacers provided. But if you had two sets would there be enough space on the notched interface to add a second and still fir the rotor?

I’m thinking you could file down the section on the Hope mount that touches the frame tab to bring the mount closer into the tab. Then buffer out the bolts used for mount to tab with washers on their outside (behind the heads of the bolts).

Your spoke hitting caliper might be improved or spoke head washers are used on the non disc side. This can help with spoke tension as well as their overall angle.

That’d be really great! :star_struck:

I would have to check. BTW, I’m familiar with filing my Hope Adapter as I’ve already done it on my BrakeFast G29 :smiley:
I’ve though about using usual disc spacers (cut in two). But I’m not sure they would fit between Schlumpf’s spacers and hub. As supplied spacers are countersunk, I’m not sure how I should deal with them. I guess I’ll have to give it a try and see how they fit…

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That’s strange. I can’t see why the spacers would need to be countersunk. Odd.

Perhaps just go back to a single washer behind the spacer to push it out a tad.

It seems you’re close to getting things to work. Did see on the French forum someone has built up a Braus wheel and it looks like they’re happy with it / it is working so perhaps there’s something to learn from their build.

Anyway. I’m really keen to find a fix for this area :crossed_fingers::gear:

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Haven’t you seen the same on your spacers? I guess it helps the countersunk screws to get in place :thinking:

I also was happy at the beginning, when everything seemed to work :upside_down_face:

BTW, I’ve just put a second set of spacers between the caliper and the adapter. It moves the caliper a bit higher and may help to get enough clearance. That’s not perfect for the pads, but I guess ~3mm would not be a big deal. The disc still rubs against the pads, but I don’t think I could do anything against it.
I’ll give a try to this last dirty fix this evening or tomorrow at noon. If it seems to work, I’ll try and ride it for ~60 km tomorrow evening! (And if it doesn’t work, I’ll go out with my G29!)

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The spacers I got as the fix for the non-fixed hub don’t have any countersink:

Even with the countersunk rotors as the spacers sit behind the rotor and against the hub body I can’t see any need for them being countersunk - only the rotor needs this for the new bolts to recess into.

Looking at a close up or a 100mm “new” hub the space for rotor and spacers looks to my eyes like enough for 2 spacers and disc just but I can’t tell for sure as the rotor has to have enough metal of the hub notching to be secure.

I hope your dirty fix proves the magic charm that’ll get this up and running without any concerns.

Note to self: I spend too much time thinking about these hubs and writing about them on these forums :joy: