Problem with one of my MU rotors…
The second one I bought is not completely true. I put it on my 24" wheel set and it wobbles so bad that once every half revolution, it’s hitting one brake pad or another. I rode with it like this to see if it got better but it didn’t… Made riding incredibly hard.
How does one true your rotors?
I have had to true my rotors on by b*ke a couple times. You can get a fancy tool but I find that a crescent wrench works really well.
You don’t want to use your fingers or pliers since fingers leave oil and pliers can scratch the braking surface with their teeth.
Edit:
I am pretty sure that the 37mm is the actual hub dimension, Makes sense to have inner lip of the bearing cap machined out to 38mm to give 0.5mm of clearance on each side.
How much would a full set up cost?
Thanks for the tip… The rotor is pretty warped. I put the 26" wheel back on and it works perfectly without any rubbing. I’m pissed I decided to take the 24" wheel today 
That sucks, I’d rather figure out how to exchange the rotor rather than have you attempt to straighten it out. Maybe it was dropped or stepped on during shipping, but we get them straight and send them that way. if it bent during a ride, straighten it… but new, you shouldn’t be dealing with that.
The other potential, is that the crank spider may be a tad off, try moving the 1mm spacers around where it’s “bent” and see if that makes a difference.
I just don’t want to send you another one to find the same issue, We had a Sinz crank that had the spider drilled a little off so the rotor deviated up and down slightly. the crank spec is for chain rings that have lower tolerances than discs do. I just want to troubleshoot first.
we want our products right, and easy to install and adjust.
$159 gets you the crank, rotor, spacers, chain ring bolts and nuts.
$15 will get you a weld on mount. ( go to a garage or technical high school and get the welding done for $50 or less) you will have to paint the weld and mount after, so not pretty on a chromed uni.
we are working on a bolt on kit to attach the caliper to the frame, but so far we are making it compliant with nimbus, KH, and maybe coker. We don’t know the spec for your Sun or K1 bearing cap. all your rigs are steel right? it’s not available yet, and we are not certain of unit cost yet.
Word… that’s customer service 
I took the rotor off and checked it, this is what I saw. It’s warped, the Sinz cranks seem fine. I need another rotor from you guys for the 29" wheel I built. Can you send me 2 and I’ll send back this one?
Wow, that’s a bent rotor! We also have to reevaluate our packaging. I’ll talk to Jeff, and we’ll sort it out.
Here’s my MountainUni family…
So far, to large marge wheel sets, 26" and 24". The 26" has Larry on it and the 24", an IRC kujo 3.0.
I am going to add a KH 38mm 29-er cruiser wheel to the family. I may also add a 26" guni wheel to it with a 3.0 tire in the future. I am just not 100% sure about getting a geared hub 
The Green powder coat is sweet. The yellow accents are nice; with the green frame and huge tire it has a John Deere tractor look to it. I’d love to see a few more pictures, the Formula caliper is hiding behind the crank arm… is it still white? maybe when we get you the parts for the 29" Wheel, you’ll snap a shot like the pic of Turtle’s set up.
Will a 29" x 2.5" tire fit the 26" Surley frame?
The geared hub is a sick concept, I hope to get our UniCaliper Mount compliant with the Schlumpf hub.
I will take more pics. The 29" 2.5 tire should fit. The 26" tire is 3.7
are you just going to paint the weld and tab, or try to paint the chromed uni?
For warping rotors, park tools makes a rotor truing fork. I use them a lot on my mountain bike because I am too poor to keep buying rotors every time they begin to rub.
Schlumpf compatibility?
Any update on Schlumpf compatibility of the bolt-on mount? A while back you had written that this is the only disk brake compatible with Schlumpf. . . was that only in reference to the weld-on mount that doesn’t work with KH frames that the vast majority of Schlumpf hubs are on?
You’ll have my order pretty much as soon as you can confirm it will work with my Schlumpf on a KH frame. Otherwise I’ll just get a maggie. I’d like to have a brake for muni-guni this year.
A couple of Schlumpf enthusiasts posted some specs of the bearing cap of a compliant unicycle. I forwarded that info to the machinist so we can produce the Uni-Caliper mount consistent with Shlumpf hubs!
The only thing is that braking while shifting the Schlumpf is not a good idea with a hub mounted brake. “So release the brake, shift, reapply the brake.” the predictability of the brake otherwise is superior to rim brakes.
Is that because the ratio change will differ the amount of pressure you need to use on the brake?
@ Dane- No, its because the hub does not like to shift down gear when there is constant torque applied to the cranks. One advantage of Magura brakes was you could use the brake to slow the wheel while you relieved pressure off the pedals to engage the shift. With the brake attached to the crank, and not the rim, it would be impossible to apply this technique.
mark
Haha, I’m one of those enthusiasts.
I’m aware of the shifting issue. I’m new to the Schlumpf, so haven’t gotten into the habit of shifting while braking. Anyhow, I anticipate that the advantages of the disk brake are greater than the loss of this one technique. It will just require a little more planning ahead for shifting.
it’s really hard to wait 
