BrakeFast Schlumpf Brake Adaptor


Some of you geared riders will know about the work that has been going on for the last 2 years on a way to fit an internal disc brake on to a schlumpf hub. The design journey has been catalogued on the Facebook Geared Chat group.

The “Brakefast” project was an open source design project lead by Martin Charrier and myself to design an adaptor to the hub that allows a brake to operate on the rim side of the gearbox and be internal to the frame. The project has had lots of helpers and supports, this is real a community project! Although I will say special thanks to Maksym Siegienczuk who found us the manufacturer.

The Schlumpf hub has always had a problem with the disc fitting on the KH moment/spirit cranks as it transferred the braking action through the gear mechanism so reducing it’s life. It also had additional installation problems.

The “Brakefast” adaptor is for the Schlumpf geared unicycle hub. This adaptor fits on to the left-hand hub flange and gives the Schlumpf hub an internal disc fitting. We have also found a relatively easy way to install a tab on the other side of the frame with the Brakefast tab adaptor

The design process was made interesting with the introduction to the market of the 32 hole carbon rim and finding out that the hubs had 2 different PCD’s.

Unicycle.com in the UK have agreed to finance a batch of these and are looking for people who would like to pre-order some. The product is on the website here, but we ask people to also express interest in an adaptor on the facebook group or contact me directly.

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Looks just like the ones I have been building for several years. Great job getting these out to the Schlumpf riders. These are really good for our geared friends.

                                                                Thanks Mark, (Lobbybopster)
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That’s a neat design you ended up with.I saw some of the earlier drawings, I like the changes that were made. (especially that all the versions are 2 piece now)

Is getting the brake disk themselves laser cut an option you have thought about? Even in low quantities, it might be cost efficient vs. throwing most of a Shimano rotor away. I’m not sure how (or if) brake rotors are heat treated or ground after being cut out though, so that may be an issue.

Fascinating! I’ve been following along some of the posts on Facebook. I’d like to throw in some basic questions for the less-technical users:

  1. I replaced my original (2010) KH frame with a later one, with disc brake mount, when I upgraded to a disc a few years ago. That mount is on the right side. I remember spending many hours with a file to get everything to line up. I haven’t had a problem with this setup, but am concerned with the “extra wear & tear” this setup puts on the hub. I’ve already killed one hub. The question: Would I need a new frame, or to customize my current one? If your photo is of one on the left side, this would appear to be a yes.
  2. What’s the weight savings with a carbon rim? I have the Nimbus one with the holes.

Thanks to everyone working on the project; a labor of love for little or no money, for a small group of enthusiasts. :slight_smile:

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The brake caliper has to be on the left with this setup. So yes you need to get a new frame - good news is: @MAD4ONE just announced a 36" frame with brake tabs on both sides. Or, cheaper alternative is to get a D-Brake adapter. In this case, it would probably be a good thing to add something to strengthen the D-Brake as the forces going thru it on a large wheel are huge.

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Alternatively UDC is also selling a weld on brake tab as well as a bracket to properly position it from a d-brake.
In the grand scheme of things, paying a welder and a powercoating place would seem pretty cheap, and no doubt cheaper than the future Mad4One frame (as nice as that’s going to be).

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D’brake tab is not a problem to use. It now comes with an anti-vibration bar which should allow it to be used on the any size rotor without a problem.

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What a nice project and piece of work! :open_mouth:

If I am to build/rebuild a Schlumpf wheel, this Brakefast thingy is definitely going to be part of it.

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I was lucky enough to be able to try out the first prototype of the BrakeFast. I rode nearly 500km in September-October 2020. I would have liked to continue, but with the restrictions due to the health crisis and the winter weather, I’m more willing to go off-road.

I really like this set-up with the 36" carbon rim, and although the braking is improved, what I like the most is to be less unbalanced when there is side wind (there is wind almost all the time in Brittany (region in the west of France))

Here is the photo album with the step-by-step assembly (the final version of the brakefast has since been simplified)

For my part, I am lucky enough to have a great flansberrium frame with brake mounts on both sides. But, for my 2nd schlumpf hub, I opted for the braketab kit (prototype too) and I had a support welded on a KH29 frame. I have other KH frames that I like a lot (the way KH frames fit the bearings is just perfect), so I take the opportunity to update them by having supports welded on each one.

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First post in ages here… I’m very interested in the brakefast adapter and curious about people’s experience with it. A few days ago I noticed the right crank on my KH36 Schlumpf with external disc had come loose. I found that the screwheads of the disc had been grinding away on the frame and the bearing housing. There is so little material left now that I definitely need to rebuild pretty much the whole uni with a new frame, cranks, seatpost etc. So my plan is to get the brakefast, a QX rgb 36“ frame (with fitting clamp and seat post) and a new pair of cranks as well. Would love to get a hold of one of those carbon fiber rims but nobody seems to have one on stock. So I guess I’ll stick with my trusty nightrider rim and save myself 600 bucks. Also I wonder if there is a better alternative to KH Spirit cranks to go with a pre 400 Schlumpf with QX rgb frame combo. Since the spirits got that close to the frame I think I should try something else.
Would be great to get some advice about it. Who knows, maybe there’s someone around here with a similar setup to weigh in?

Currently there has been only a few people who have tested the BF adaptor. One of them is @toutestbon.
Basically, any internally-brake-compatible frame with 100mm bearing spacing should work (RGB, Flansberrium, future Mad4One and Nimbus).
Regarding the cranks, any good ISIS set should work. @toutestbon got a set of Nimbus Venture 2, but you have other choices.
Getting a BF adaptor would probably be an excellent choice of yours to preserve your Schlumpf hub using a disc brake.

Bad news, guys. My BrakeFast failed on Monday. I don’t know if it’s human error of parts failure but you should check yours for loose bolts.

Here is what happened on my BF32:
9 out of the 18 screws have been cut by the efforts I put in my wheel. That’s a complete half-flange that came away from the Schlumpf hub.

image

It could be a human mistake as I did all the assembly without having a log of experience. I have followed the video explaining how to assemble the BF with the hub except one part: filing the inner side of the hub flange. I think it may be the issue even though the potential gap couldn’t be seen at that time.

As of the the clues that could have told me before the breakage happened:

  • the wheel felt untrue for about 2 weeks. I thought it was normal because of my poor experience in wheel building. There were 2 untightened spokes that I tightened again 10 days ago.
  • the disc brake felt untrue, too, as it rubbed against the caliper. I replaced the caliper and it was then mainly quiet.
  • the uni has started to clicks on Sunday - the day before the breakage. I thought it was my brake so I didn’t pay much attention to it and it resolved by itself before coming back on Monday evening.

A few pictures of the half flange:





2 of the 9 bolts miss their head, so I don’t know if they broke before Monday - I have had a brutal UPD on Thursday, it may have been because these screws broke then.


You can also see that all the screws parts are still in the BF. I don’t think there’s any way to remove then now.

Finally, it has damaged one of the disc bolts. It can’t be screwed again.

So… Please regularly check your BrakeFast doesn’t become loose and doesn’t make noise. It could be really dangerous otherwise.

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Something went wrong with your picture uploads (or at least I cannot see them).

I have had the same issue before refreshing the page. Could you try to do so?
I think we’ve had the same issue on the french forum. @Canapin, I have copied/pasted most of my last post including images from an email sent on Gmail. Do you think it could have break something?

The problem is, that you inserted the pics as links into your email inbox.

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You’re right. Links in my post pointed to Gmail URLs. I thought it had copied the pictures instead of the links. :unamused:
Well, that should now be fixed. Thanks!

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Whether it is user error or parts failure, it is not good and needs addressing. Can we design this problem out? I am not sure.

The failure has happened due to movement of the flange from bolts coming loose. Noise is generally the sound of movement and should have been checked immediately.

I have just checked mine and I have no movement in mine, but I am not as much an awesome rider as Maxence and probably do not put as much load on the system… but this needs to work for everyone.

So first of all we need to warn the others to check their brakefast for noise or movement.

Martin has a suggestion is that we tie the two half’s together - this will definitely help. If we can do it with small steel plate and put in super long bolts an Ni-lock’s on them it would give us a different connection. Potentially possible to do in retrospect.

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Very unfortunate! Was the hub damaged in any way?

Can anyone else comment on the lack of filing the holes as a potential reason? I have also skipped this step… (haven’t finished the wheel build though)

The filing of the flange will help as it gets a better connection… this may have contributed, but I am not sure.

I build my flange super badly to try and test it and I have not got a problem with mine *(but as I say, I am not a super trough rider). The one thing I did do what file the flange before building… I can not believe that is the key thing.

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At this point did you check that a gap between the BF and the hub was not the cause of your untightened spokes?

With the prototype, when the hex screws came loose (before switching to torx screws), I first felt that the wheel was untrue before I realised that there was play between the BF and the hub flange.

The fact remains that the screws have come loose when they should not have.

How long/distance had you ridden this unicycle before you felt the wheel untrue?

If it’s any consolation, I didn’t file the hub flanges and I rided 1000 km on my G36 with the prototype, and 400 km on my G29 with a BF36. I have not heard any sound from the BFs (since I switched to torx screws).