ok, so far i’m very happy with the disc brake! …but my pads are allready down 
the disc is getting very hot (needs more holes), so the pads ar going down pretty fast… i run the shimano slx, i’m changing know to the xt, and i’m waiting for an even better one 
Wow… can you get sintered pads for your caliper? So far, I am loving the Formula Oro K24, I need to get some spare pads because I am a little worried about the heat distribution of the MU rotors. Given you recent pics… you may be “over-testing” your brakes 
“I’ll struggle with details, for you folks… it will work. has anyone had headaches trying to put this together so far? These will be done Friday!”
Please PM me with any questions, it will be a pleasure believe it or not.
You are witness to 47 pages of transparency my friend! MountainUni is two guys that have sunk a fair amount of $ into this project, kept 2 machinists and a fab shop on task and we have a cutting edge marketing team on the not yet website. the hold up… pictures! We have secured a distributor for small parts, one for unicycle parts, one for unicycle frames… and we just want it “right”. Everything will come together -even on your uni dude. The FaceBook page is filling the void for now.
The transparancy is a double edge sword. You know what will work and what we’re figuring out as we’re figuring it out, (and so does our competition that is racing us to produce 2 products -major manufacturers producing stuff in Taiwan.) Even so, our products are not cast, but machined from billet in the USA. I am certain that Josh would have gotten the Impulse and Oregon off the ground, but do you think it would have happened so soon if we hadn’t started innovating? I believe that the thread kicked others into action over “an old idea” that obviously hadn’t worked until we proved it. We have bigger plans, and plan on products that are technically superior.
Don’t fear the unknown, trust what you do know… we have likely sold the amount of systems equivelant to the amount of Impulse unis sold in the US, with the same amount of satisfaction at a third the price! You’ve seen the feedback from the users -anyone can post here! The system works.
We intend for our UCM to be compatible with ISIS 42mm bearings, to work with our 180mm outboard rotor on the right -Schlumpf Hub compliant, or possibly on the left side inboard 160mm-203mm rotors, for bearing cap bolt patterns from 54mm-60mm, and function with 6mm-8mm crank stop spacers… for $65! Granted, the more universal something is, the more tinkering may be required, but we will come up with recommendations and guidelines… although not yet completely outlined, as it is just being produced now. The weld on mounts are not standardized mounts -the UCM will be. So, get a front 180mm iso adapter with the brake and you’re golden.
And MountainUni does appreciate your interest, thank you for your post!
Wouldn’t more holes make it hotter? If the radius of the hole is more than 2x the disc thickness, you are loosing radiating surface area. I thought the holes are for weight savings, not cooling.
We may not need as many holes actually. I suspect the holes are helping with the wear and cool the rotor less. the holes are actually for high speed and allow the rushing air a place to escape so the pads can strike the rotor effectively. Unicycles will never see such speed at the rotor. The rotors are currently made of 304 stainless, and unlike 400 series, the rotors are truely stainless but they don’t heat treat like 400. We’ll see about material changes once we start thinking of weight savings and future design, when that time comes.
Somebody else understands this better than I do, but I think more holes gives more surface area to radiate heat off the disc into to the air.
Edit: never mind kb1jki beat me to it
at may LBS they told me, more holes: better for cooling (but also wear down more), the holes are also good when the brake is getting wet ? …anyway i’m very happy with my three wheelsets withs the discs (also a schlumpf one) have nor problems and didn’t cost me 1200 $ (3 pairs of cranks and 3 discs,one brake, one triton frame) 
and by the way: 1200 bucks for three perfect unis isn’t much!
Hmm, good point about the holes allowing better pad contact. Though it can’t be that important because none of the cars I’ve replaced brakes on have them. I think you are correct about rotor speed; with the low speed of a unicycle wheel, I don’t see them creating any significant airflow to help with the cooling.
If the holes have a radius larger than twice the thickness of the rotor, they lower the surface area:
Surface area removed to create hole = pi * [radius of hole]^2
Surface area of “hole wall” = 2 * pi * [radius of hole] * [thickness of rotor]
So a hole that cools as much as the area removed will have a radius at most 2 * [thickness of rotor]
I can see how the holes help on race motorcycles, but I think that on unicycles (and probably bicycles) they are more of a style and weight thing. The holes definitely make your rotors look good. But I think that for guys like Turtle who ride down impressive mountains, a solid rotor is more likely to stay cool.
Thanks for the feedback, that was the information I needed. Maybe that needs to be made sticky somehow? Note that some folks, like me, cannot access twitter or facebook from work.
I totally understand the time and effort that’s gone into this product, it was almost a shame that UDC did their own system vs the two systems coming out as one, but it is what it is.
It’s a hard decision for me, esp with Schlumph not likely to be disc compatible anytime soon. I’d feel better knowing there was at least one other compatible crank.
So is there another crank choice?
For those riding Sinz, how does the Q factor compare to KH?
I haven’t tried my rotor in hard conditions but it was a pleasant experience to ride some downhills with a brake today. I attach two photos of my uni yet without a T-bar. I’ve already mounted it, but as it is dark I’ll take some outside photos tomorrow 
I have been riding all of my normal trails withe the Sinz and before that, had KH cranks, if there’s a difference in Q factor, I don’t notice it.
Ok, I just think they make it look good. Oh you already said that too. I agree!
I like the spindly-looking ones I see on bikes, with a minimum of material. But then, I think I’d go for practicality in this case if it’s going to make a real difference with pad wearing.
what seat is that?
Jtrops has successfully used a chopped down Doteck crank from the 80’s but it was square taper I believe… So far Redline and AC mini cranks have been ruled out. the spider on the Sinz keeps the rotor far enough away from the frame to prevent chain ring bolt rub. Bmx cranks also come in the smaller sizes but the spider “dish” needs to be shallow.
I flipped cranks around and measured across to determine Q on both KH Moments and Sinz Experts. See attached photos:
The frame, Rim, and chain ring bolts are all blue! it looks sweet!
OK, really now…
I see you have the UCM for sale on the FB page. I want a disc brake on my KH/Schlumpf-29. I don’t see any reason this UCM won’t work. Am I right?
So I get a pair of SINZ cranks (which will fit on the KH/Isis splines, right?).
Then, from you guys, I get a UCM and the rest of the disc hardware to go with the SINZ cranks I buy, right? So UCM: $65 + (disc hardware -SINZ price): $89 = $154.
Then I need a brake. Which one would you recommend at this point?
Then I’m shredding?
just wanted to let you guys know that i finally got the brake on. it’s amazing! the braking is so smooth, i havent gotten to test it thoroughly but from the little i have i love it! thank you guys so much for the wonderful product!
james
Your math seems sound. I would recommend the Gusset Chute 180mm hydraulic front brake which we attached to the UCM prototype on a KH.
You should be able to also bolt up a Shimano front 180mm Hydraulic disc brake onto the UCM.
sku 171574:
http://www.chainreactioncycles.com/Models.aspx?ModelID=48577 (tested)
http://store.icyclesusa.com/brake-disc-ash-pc-b-pancake-hydraulic-front-lever180-p36875.aspx
http://compare.ebay.com/like/120668455687?ltyp=AllFixedPriceItemTypes&var=sbar
or use whatever hydraulic disc brake and get an adapter:
http://www.mcconveycycles.com/store/product/5940/disc-brake-mount-180mm-international-standard-fork--post-caliper-front/
We are currently researching lesser expensive Mechanical disc brakes but can not yet verify what Mechanical disc brake works. Once we find a Mech brake, our system will meet the price point of new maggies alone, which was the goal from the onset!
We intended and designed the UCM to be compliant with Schlumpf and expect it to work but untested. We will offer money back in exchange for the UCM if it doesn’t work and we will figure it out. We will be sending one to Florian for his approval. Jogi has been running 8mm crank stop spacers with Florian’s blessing for a year now without issue. You will need to use the crank stop spacer for the system to work consistently. You can test it or wait for the word from Schlumpf or other Schlumpf hub users.