When to expect the disc KH cranks

I received my brakes with adaptator but if yours is delivred without, you can use this one http://www.chainreactioncycles.com/Models.aspx?ModelID=69495

Terry, this is a non issue. If the brake torque is so significant, then the frame will twist under braking anyhow, causing uneven pressure on the bearing cap, which will cause the same non problem that is worrying you.

For a counter perspective, Josh at UDC said that one of the reasons they went away from frame mounted disc brakes is because it was twisting the frame. He added that by placing the brake caliper on the the bearing holder, the torque was more controlled and LESS of an issue because the wheel/bearing moves with the bearing holder unlike the frame which would be twisting above the bearing holder.

Now back to your scheduled program…it’s June already, when are the cranks coming in??

Your quote from Kris does not at all address the issue of frame vs bearing cap mount, so I’m not clear on what you’re deferring to?
Speculation aside, I hope and expect we’ll get some guidance and instructions on use of the disk-mount cranks when they are released.

Not to mention, you can put the knurled bearing on the side opposite the D Brake if this is such a concern.

The D Brake adjusts diffently than a normal bearing cap, but it is designed to do so by having one side “set” while the other side is used to establish bearing pressure.

In all liklihood, it is a BETTER way to manage bearing pressure since with a typical bearing cap, both sides of the bearing cap “gap”, whereas the D Brake has one side set with the upper and lower caps flush, thus it reduces bearing movement and is MORE secure.

I think UDC should design all of their bearing caps so that one side is adjusted flush and the other side is used for tensioning, it makes more sense to adjust tension from one side vs two.

You need a front brake IS adaptor, most brakes come with one specific to your disc size (160, 185, 200).

A “front” brake will have a shorter hose, so that’s your best bet for a muni, though it could still be little long. A “rear” brake might be a better choice for a 36er where you have the brake mounted on a touring bar out in front of the seat.

The brake description will often list the hydraulic line length, so measure what you use for your Magura. If measuring with no brake at present, be “generous” in your estimate and add in a frame wrap or two if you think you’ll be using it for more than one mounting style in the future.

There are lots of opinions on what disc size is best. I have a 185 on my 36er and 160’s on my 26-29, I don’t have problems stopping with the smaller disc, but some brakes/pads are better than others, so keep in mind that a bad pad will make a good brake work poorly. Organic pads tend to be the best choice, but most disc brakes come with semi metallics, which work fine most of the time.

At this time, there is not a mechanical brake caliper that will fit with a unicycle disc brake, so hydraulic is your only choice. The are some reviews posted under the disc brake thread ini reviews.

Front front front!!! Rear has a 10mm different position to the front requiring a 20 mm larger disc for the same sized adapter (a 160mm rear adapter is the same as a 180mm front adapter).

Most brakes that come with a disc rotor come with an adapter but remember to buy a front setup as that is what the Dbrake mount is built for

Read this thread for all the info in this thread

Again, I am only talking about the dbrake application for a schlumpf hub, and that both bearings have to be tightened to a specific torque, which may be exceeded by use of the dbrake. I will wait for someone else to use the dbrake mount on their schlumpf, and wait for their ride report. No hurry here. I’ve been very happy with my magura, but it would still be nice to finally have a disc brake option for the schlumpf, while still being able to use the [new version] moment cranks.

Huh? Are you talking about measuring how long your magura brake line is and then getting that length for a disc brake? Or have I misunderstood what you said? Cause if you order a brake line for a disk brake the same length as your magura line then chances are it will be too short.

Yeah, I’m pretty sure that’s what Ben is suggesting.

Actually, with the KH disc cranks, the dbrake goes on the non-knurled side of the hub, and as such only must not be tightened more than 5nm. That’s plenty tight to keep the dbrake in place, so this is a non-issue as long as you are paying attention.

You can mount a schlumpf either way round depending on which way you prefer the buttons
I and I think most people have the gold up shift on ther right and silver down shift on the left
Would this put the d brake on the right (gold) non knurled side?

Good question, especially as I am a Southpaw with the up button on the left and down/normal button on the right.

The blog entry from UDC uk with the 36 inch schlumpf
Penny that feisty linked to earlier. Shows a shlumpf with prototype new KH cranks and a d brake mount. Looks to be clear that
It can be done. So is it known this is a modified ( belt sanded) mount? Or can it work as is?
Also is it going to be more difficult for left foot upshifters? Or can the d’brake be use on the knurled side?

Yes, you’re going to add some hose for the leg length, sorry if that wasn’t obvious :roll_eyes:

Something that may also not be obvious to folks who have not used a disc brake on a bike: they can be sqeaky and they are heavier than a rim brake.

Between the weight of the brake caliper, disc, and adaptor, you are looking at 100-200gm added weight over a Magura rim brake. The benefits of a disc brake are more stopping power and improved wet weather braking. You will also have some brake pull to the side the brake is mounted, but you will no longer have brake rub on the rim.

Overall I have enjoyed disc brakes, but I have had some issues with grabby brakes on my Tektros, which are metallic pads, so I have ordered organic and ceramic pads to see if performance is improved. My Shimanos and Bengals have had no problems

If you are not overly flush with cash and you already have working Maguras, then disc brakes are not all that “essential”. But if you have been thinking about getting new cranks and you don’t have brakes currently or your Maguras are mucked up, this would be a nice way to upgrade.

For $100 you should be able to get a decent disc brake. Shimano is a good choice, any of the 500 series are going to be fine, many can be found as “take offs” from montain bikes. The Bengal that UDV uses is a off brand copy of the Hayes.


I think you’re sweating this stuff too much, it’s just a brake, the Schlumpf is just a hub. I had no problem hand snugging the bearing caps on my guni, being a long time mechanic it was not a problem to avoid overtightening, so I’d expect as a piano tuner that you have similar tool user skills. The folks that had problems with bearing failure from overtightening were not given guidance as to the risks of overtightening, but since then I don’t believe there have been any external bearing failures.


Schlump plus D Brake, seems to work fine.

That’s simply not true. According to Magura themselves, an HS33 is 464g. Plenty of disc brakes weighing less than 400g - for example a Magura MT8 weighs only 310g including the disc according to exactly the same source of information (personally I have Formula R1s on my MTB which come in at under 300g, and when I get a disc brake on a uni I’ll probably reuse one of my old B4SLs which I replaced with those, but which are a similar weight) . I presume that doesn’t include the adapter, but then one of those is only ~20g, still making the disc brake far lighter.

Hey All,

I’ll make a full announcement about all the new KH gear late this week…=)



Looking forward to getting a new 36er!

Excellent! :slight_smile:

To clarify: it doesn’t matter whether a d’brake 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. There’s 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 hasn’t 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, I’ve added a warning to the assembly instructions to use the crank-mount disk system with KH/Schlumpf hubs at your own risk.

I don’t want to scare anyone and the disk brake/ guni combo has been amazing setup that I’ve 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.