Nimbus D-brake -vs- Mountain Uni UCM brake mounts

[gdrambler]

I have a 24" Impact frame with a 24" KH wheel set. Have yet to put anything together. Desire to have internal disc brake. Any idea’s if d-brake will work? I know the KH disc brakes are mounted externally, why? If d-brake would work, what would be best brake?

Thanx

[saskatchewanian]

If you want a internal disk you would need to get a new hub and completely rebuild your wheel, as well as a disk break adaptor and break. If you decide to go external you just need some new cranks with the brake and adaptor, and as a bonus you get strong light dual hole cranks.

[Rod]

@Eric aus Chemnitz

Yes, I designed it myself after measuring the bearing housing and the d’Brake and hat it produced by a friend. … I can provide CAD data or manufacturing drawing if needed.

Very nice. What type of shop could produce it? What type of material would be suitable? I would like to have the information to have one made. Could you pm the info?

Thanks!

[Eric_aus_Chemnitz]

@Rod

Very nice. What type of shop could produce it? What type of material would be suitable? I would like to have the information to have one made. Could you pm the info?

Thanks!

I had it produced via SLM (Selective Laser Melting … 3D printing with metal) out of steel (don’t know which alloy). I think any sort of normal steel would just be fine (e.g. S235JR) or even aluminium. It must only take compressive forces, not more. It can be produced by any manufacturer that has a small cnc milling machine out of 6mm flat steel.

I PM you the CAD data and drawing. I did this construction for a Qu-Ax steel frame. I’m not 100% sure if it fits any other steel frame. Just plot the drawing 1:1 on paper and check if the groove will fit your frame.

[Eric_aus_Chemnitz]

Please post a photo when you have it produced.

[Eric_aus_Chemnitz]

@saskatchewanian

Eric aus Chemnitz brings up a good point. The MU UCM has a flat top compared to the D’brake’s staggered surfaces. Where the D’brake is tightened on the side with the arm first then snugged up on the other side the UCM would be installed like a normal bearing holder.
[…] I now use a washer under the arm side of the UCM to transfer the force to the frame like the D’brake does and both need to be shimmed out to work with the KH cranks as the Spirit cranks place the disk a bit further from the frame than bike cranks with a MU disk would.
…

@Eric aus Chemnitz

I did not know, that the UCM does not provide this staggered shape. So thats plus for the d’Brake. It’ll make no sense to tighten the bearing holder with a defined torque for not deforming and so damaging the bearing and on the other side let the whole brake force go radial right into the bearing just to deform it to egg shape.

I wonder if riders with the UCM therefore do have damaged bearings a bit more often. Did anyone have issues with that?

So here it is: we now have the first broken frame caused by the UCM Caliper:
http://unicyclist.com/forums/showthread.php?p=1662619#post1662619

[Eric_aus_Chemnitz]

I think this belongs to this thread but was not mentioned here yet:
To avoid broken d’Brakes, Hugo from the german part of the forum designed a strut to support it. We call it “Hugo Strut”. Many riders have installed one to their d’Brake yet. It also helps against vibration noise
This is how it looks like:

[MrImpossible]

@Eric aus Chemnitz

I think this belongs to this thread but was not mentioned here yet:
To avoid broken d’Brakes, Hugo from the german part of the forum designed a strut to support it. We call it “Hugo Strut”. Many riders have installed one to their d’Brake yet. It also helps against vibration noise

I’d like to figure out something like that for my Oracle frame, which doesn’t have the magura mount to use as an attachment point for the strut. The stock brake worked fine, but I had to replace it after a crash, and I’ve had a terrible time trying to make the new brake stop shuddering.

I’ve tried things like cleaning, sanding, replacing pads, replacing rotor, no help. I finally stopped it by forcing a little bit of toe-in on the pads, but I don’t like the solution, so I’d love to find something better. Has anybody tried something similar to this, but just clamping it to the frame leg somehow?

[finnspin]

@MrImpossible

Has anybody tried something similar to this, but just clamping it to the frame leg somehow?

Yes. A strip of flat steel, a m6 bolt and nut, and some aluminum tube (I believe I used 9mm diameter) will do the trick nicely.

Bend the steel around the frame leg, drill 2 holes through it. Hammer one side of the tube, drill a hole large enough for the bolt on the brake mount to pass through. Shorten to desired length drill another hole through the tube for the frame clamps screw to go through. I used a different pickup on the D brake than the one Eric posted (the one where the post mount adapter is bolted to the bearing holder) I can dig out pictures if you want.

It really helps a lot, much less vibration under braking now.

[Eric_aus_Chemnitz]

@MrImpossible

Has anybody tried something similar to this, but just clamping it to the frame leg somehow?

Yes, Charly did:
http://www.unicyclist.com/forums/showpost.php?p=1641340&postcount=57

[MrImpossible]

Thanks for the replies - I’ll give it a try.

[Eric_aus_Chemnitz]

and this is, how the solution looks like on an Oregon:
http://unicyclist.com/forums/showpost.php?p=1641531&postcount=28

[MrImpossible]

Here’s my first pass at a fix, just using things I had lying around; I haven’t had a chance to really try it out yet.

[Eric_aus_Chemnitz]

This is the comparison of forces on the d’break (top) and the UCM caliper (bottom)

[chainreactionphysics]

Got a large vibration when doing steep downhill today. Checked this thread out and made a heath robinson fix.

I used an old cateye light clamp and a bit of metal from an old b**e rack.

Seems to work on light braking - test in anger later.

Stewart

[lightbulbjim]

Posted elsewhere already, but… another one for the collection. Improved braking massively on my 36er.

[Eric_aus_Chemnitz]

@lightbulbjim

Posted elsewhere already, but… another one for the collection. Improved braking massively on my 36er.

Is there any connection between the tube and the brake adapter (thread in the tube?)? Or didn’t you attach both parts to another because the brake force will always push the adapter onto the tube?

[lightbulbjim]

@Eric aus Chemnitz

Is there any connection between the tube and the brake adapter (thread in the tube?)? Or didn’t you attach both parts to another because the brake force will always push the adapter onto the tube?

The bolt is extra long, and protrudes about 8mm beyond the adapter. There’s a piece of 8mm diameter aluminium rod about 12mm long which is drilled and tapped and tightened onto the protruding bolt. The strut tube has an ID of 8mm so it fits tightly over the stub. The tubing is bent very slightly to line up the bolt and hole in the frame.

So to answer the question, it is quite securely aligned but is strong in compression only.

[lobbybopster]

Secure Rod

Hello lightbulbjim, I like your torque arm ! , how would this action be effected if you drilled and pinned the 8mm x 12mm rod (internal) to the outer tube ? Would the ability to no longer expand cause any vibrations ?

       Mark

[Eric_aus_Chemnitz]

@lobbybopster

Hello lightbulbjim, I like your torque arm ! , how would this action be effected if you drilled and pinned the 8mm x 12mm rod (internal) to the outer tube ? Would the ability to no longer expand cause any vibrations ?

       Mark

I don’t think so. Because all the others I’ve seen so far, including mine, have no ability to expand and all help against vibrations.

Nimbus D-brake -vs- Mountain Uni UCM brake mounts

I think this belongs to this thread but was not mentioned here yet: To avoid broken d’Brakes, Hugo from the german part of the forum designed a strut to support it. We call it “Hugo Strut”. Many riders have installed one to their d’Brake yet. It also helps against vibration noise This is how it looks like: [image] [image]

I’ve put a thin layer of rubber between every part (frame - d’brake, brake-adapter - hugo-strut, hugo-strut - frame) but I don’t thik it was necessary. Hugo (who built the first of theese) used no rubber at all and was able to eliminate all vibration of his brake with this strut. I’ve also put a bit of pre-load on mine in hope that it might support the d’brake even better.