Excellent! 
To clarify: it doesnāt matter whether a dābrake or frame mount is used. By definition, 2nd gear works on the geared hub by bracing the turning pressure against the knurled bearing, which is held in the frame. Thereās no pressure on the knurled bearing in 1st gear, only second.
With crank-mount disk brakes, the braking force runs through the crank, obviously. That means that it imparts pressure on the knurled bearing side, same as pedalling or foot braking. Per above, this imparts pressure on the knurled bearing only in 2nd gear, not first.
So far in testing this hasnāt resulted in issues, except for when I forgot to tighten my bearing housing after assembling the wheel. I have not heard of this issue with the Mountain Uni / Sinz crank setup, which has been used by quite a few guni riders over the past year.
However, with release of the new KH disk crank system very soon, this braking approach is about to get much wider distribution and testing by a lot more riders.
In my opinion, not enough riders have really tested the crank-mount disk brake under enough conditions to ensure there will never be any slippage issues with the knurled bearing. My guess is that it will be a problem for someone out there, for sure. Because slippage of the knurled bearing will likely cause an instant wipeout, Iāve added a warning to the assembly instructions to use the crank-mount disk system with KH/Schlumpf hubs at your own risk.
I donāt want to scare anyone and the disk brake/ guni combo has been amazing setup that Iāve been riding for over a year now. However I do want to be transparent about the risks. Maybe add it to the long list of ways that you can wipe out on a uni =)
None of the above applies to a single speed hub, obviously, where the crank-mount system is proving to be an entirely beautiful setup for running a disk brake on a full strength wheel.
Kris
Thanks Kris for the clarification and detailed info. Another concern issued by a few others is that they feel the frame mount may cause flexing as opposed to the dbrake mount. Obviously you have been testing your disc brake system for over a year, so what are your findings in this regard?
In either case the mount is positioned at a well-supported part of the frame, so I donāt see either being relatively more prone to flexing. Certainly itās not something Iāve had a problem with.
In terms of bearing or frame mount, there will be pros and cons to each. In the case of a bearing mount, it makes for easier and less expensive frame production, because you donāt have to worry about precisely aligning the IS mount on the frame, and it potentially allows for disk brake retrofits to non-disk frames. In the case of the frame mount, itās lower profile and the disk caliper conveniently stays fixed in place when you take the wheel off. In the case of a higher-end frame like the KH frame, I chose to go with the frame mount for these reasons, but it really comes down to a balance of priorities.
hey Kris,
Looking forward to seeing what you have been working on over the last few years! On the crank mounted disc brake on a schlumpf- I was wondering about a specific riding situation that you might be able to give a report on. How do you manage to downshift to low gear when you are riding down hill, hard on the breaks? The transmission of braking forces through the hub would not let the hub engage the shift would it? I am asking because one of my favourite shifting techniques from High to low when riding downhill is to use the rim brake to alleviate the forces transmitted through the hub to engage the shift.
Iām looking forward to seeing the new gear- and hopefully getting to meet and ride with you in Italy for UNICON! Are you going to compete as well?
Cheers,
Mark
I was wondering about that too, before I started using the setup. It will depend on the rider but it was better than I thought I would be, because you can actually shift, in terms of clicking the button - it just wonāt engage. Taking the brake off for an instant will let it engage. It takes a bit of time to get used to, but it works fine.
My wife and I are going to UNICON with our baby daughter Nola so itās really more a family holiday. Weāll just be there for the first half. To be honest I havenāt had much time to ride in the last few weeks since Nola was born, so wonāt be in the greatest shape but it will still be great to see old friends and meet a bunch of people Iāve only yet known online.
I wouldnāt use the mfg listed weights if I were you, instead try weighing some as I did 
Iāll admit that I was also suprised, but facts is facts; I even went as far as using a sharpie to write the weights on all the parts; I posted the numbers on the Oracle or Oregon thread.
I imagine you could get close with an ultralight, ultra expensive disc brake, but if you want the lightest set up, Maguras are it; unless you can rig up some cantis
Ask Bryce to chime in with some Magura weights, he probably has tons of them lying aroundā¦
mountainuni brake system and kh/ schlumpf hub works (of course florian doesenāt recommand it).
really looking forward for stronger (kh) cranks, drops iām coming back!
Iāve chatted with Florian about this. That discussion related to whether it was OK to use a spacer between the bearing and the crank.
Itās really not OK. I did this on an early prototype of my system and started to have issues with the bearings. Unlike an ungeared hub the bearing lacks support on the other side so it creates lateral deformation thatās not good for the bearings.
However, much of that issue had to do with Sinz cranks, not whether you need a spacer. Based on the fact that people were having spline creep issues, I suspect the Sinz cranks are 6000 series aluminum, which is softer and more prone to this. In contrast, Moment cranks are harder 7075 Al, and the new cranks (more details tomorrowā¦) are forged from 7050 Al, which is similar to 7075 except with slightly greater resistance to stress corrosion (fracturing). Iāve not experienced any issue with running this setup with the geared hub, in terms of creep on the splines.
The potential issue has more to do with the possibility of slippage of the knurled bearing. As Turtle mentioned, quite a few riders have run the crank-mount system with geared hubs with good success over more than one year of riding, including myself. But as mentioned above, itās possible, so worth noting just in case.
Kris
Are you going to release pics and specs? Iām curious about the Q factor.
Hey Kris, in reference to Q factor, are the Moments and the KH hub specād to the āShimanoā offset, so ~150mm pedal to pedal width?
Do you still find this to be an optimal width?
The reason Iām asking is that I have been riding your set up (Moments and 100mm hub spacing) since I learned to ride, but have since added an Oregon (125mm hub) with QuAx cranks which are ~175mm in width and now Iām riding the Oregon hub on a 36er with some 175mm Try All cranks which have a more than 200mm in width.
I have not noticed any decrease in ride quality, the wider stance is more comfortable and I seem to have more stability, what I notice most is the wider stance has less seat rub/crotch abrasion.
Seems too obvious and Iām sure it must have been considered before, but with the potential seriousness of slippage (more so with a disc brake than with a rim brake) why rely on just a knurled bearing? Some sort of solid lug into a hole in the bearing holder cap would seem a simple solution. If the problem was compatibility with existing frames, it could still be knurled but have a hole to insert a little key piece if using the correct frame.
Rob
I have. The ones on my MTB are <300g including adapters (and everything else). Sure theyāre expensive, but there are plenty of disc brakes close to that weight, some far cheaper - for example a Magura MT2, with a claimed weight 120g less than an HS33 for much the same price as a Bengal. In any case, you didnāt mention cost when you suggested āyou are looking at 100-200gm added weight over a Magura rim brakeā, and Iām happy to acknowledge that a disc setup is likely to cost more in total than a rim brake, though you donāt need to pay huge amounts to get a light disc brake.
I used to spend plenty of time hanging around on weight weenie MTB forums where other people weighed their parts and published the info. The argument about rim brakes being lighter than disc brakes was done long ago on there - the only rim brakes which are lighter than the lightest discs are now fancy expensive custom V brakes, standard Shimano offerings are heavier. Maguras have always been known to be heavy, and heavier than even a fairly standard disc brake - hence I donāt own one to weigh, so instead I checked out what others had weighed them at http://weightweenies.starbike.com/listings/components.php?type=rimbrakes - in comparison to user weights for disc brakes at http://weightweenies.starbike.com/listings/components.php?type=discbrakes However the weight for Magura rim brakes on there are rather old, hence why I was using published weights - youāll note that Iām using weights for a Magura disc brake, taken from exactly the same Magura website as I got the weight for the HS33. I canāt see any reason why their claimed weights for the disc brake should be more optimistic than that for the HS33, and in any case, Magura is known to publish reliable weights (I did a bit of checking, and found some independent weights for the current gen Magura disc brakes which confirm their published specs). In order to be heavier by the amount you claim, the disc brake would have to be roughly twice the published weight!
Hence I stand by my comment that a disc brake is actually lighter than a Magura rim brake - reliable numbers supplied. I did a search on here for a post of yours where you provided weights, but all I could find was a previous post where you made a similar claim about how much heavier disc brakes are - maybe you could help me out here, as it should be easier for you to find the post where you gave the numbers, so we can work out why thereās such a huge difference in our positions (hereās a search for posts of yours containing the word āMaguraā for example http://www.unicyclist.com/forums/search.php?searchid=4511574)
Bronson Silva also said āItās not OKā when he built my geared KH 36er. I got a Magura rim brake and Iām fine with that. Iām no engineer (The Schlumpf hub is a magic black box to me) so I figured Iād have him build as per your design. Thatās also why I had him use Moment cranks.
I did a side-by-side test before I sold my Nimbus {disc brake} Impulse 36er. There was very little difference between the disc brake and the rim brake. It should be noted that all my Cokering is done on rails-to-trails asphalt bike paths and rarely in the rain.
I waited a long time for UDC to release the 26" Nimbus Oracle so I could have a disc brake on my MUni. Itās more of a low maintenance issue for me though I did learn (thanks Brycer) how to reassemble Maggies when UPS damaged my KH36G in transit (thanks Amy for the free replacement). It was not too awfully complicated to get them to work without rubbing.
I will replace the 150/125 Moments on my geared 36er with the 137mm single hole version of your new cranks so that my FiveTen Impact size 10 shoes can reach the shifting button without needing to ride on my toes. I was accustom to spinning 125/110ās on my āfixedā Impulse but geared Cokering requires more leverage. Come to think of it, Iāve never switched from the 150mm hole. Perhaps I should at least try the 125mm hole in 2nd gear before I place my order. Iām waiting on the the rumored lightweight 36" tire anyway. I want my LBS to replace everything at once. Iām going to insist they read the Schlumpf manual before they touch it.
Anybody want to buy an unused set of torque wrenches? My mechanical prowess is limited to tightening (with my $50 torque screwdriver) the shift buttons. I need to go to Park Tool school.
I no longer have Maguras and all of my disc wheels and disc brakes are mounted.
But since I did a weigh in already, and saw the numbers, you can be in denial all you want, but the disc brake is heavier whether you like it or not
If you want to make comparisons using the lightest disc brake, then you probably want to be fair and use the lightest hydraulic rim brakeā¦
I like the disc brake two reasons:
Better function when wet
No rim rub
Otherwise, they are heavier, more expensive, more complicated, have more issues with squealing, tend to be a pita, and they pull to the side.
Last night I upgraded to organic pads on my 26 an 29 to see if I could prevent the glazed pads and the associated squeaking. Iām afraid that I will end up going to a different brake because in the past I had āsqueakersā and more often than not it was the brake and not the pad.
On a bright note for UDC, their Bengal disc brake has been pretty good to date, but the white color is not for me. I went on Ebay and found a source for Bengal Helix hydraulics in different colors, blue, red, black, gold
I find the best brakes are my legs 
Right now i also have issues with my Shimano-brake + koolstop semiorganic padsā¦ they scream like hell and the whole uni is vibrating when i pull the brakeā¦
And the braking power is not as good as before (right now it kinda sucksā¦).
The issue occured after my last tour with a very long downhill-section (800 meters in attidude), whole time brakingā¦ they got freaking hotā¦
Hey all - more info on the new KH Spirit Disk Cranks at krisholm.com (here), and on the new forum thread.
Iām so glad you did away with the threaded inserts! But I wish the new single hole cranks were available in 150mm size, since I have no use for dual holes on my G26er. And Iām also surprised to see that the disc brake compatible cranks are only available in the dual hole version. Do you plan to make the single hole version in 150mm, or is 137mm going to be the max?
Between the 110, 127, 137, 110/127, 110/137, 127/150, and 137/165, thatās already a lot of crank models.
Adding the second hole didnāt result in major āhot spotsā in stress analysis, and it reduces weight. So there didnāt seem to be a disadvantage to adding it to all the cranks, even for riders (including myself) that donāt typically use the shorter option. The fewer models there are, the better the likelihood is that a KH dealer will actually keep them in stock. So currently I do not have plans to offer a single hole 150 in the disk version.
Ok thanks for the info.
So give me the numbers you have then - Iāve given you mine which clearly show that an Ā£85 Magura disc brake is 120g lighter than an HS33. Iām not the one in denial here!
Remind me again what the lightest hydraulic rim brake is and how much it weighs (for comparison with numerous light hydraulic disc brakes - eg any 2012 Magura disc, several Formula ones and several Hope ones)?