The same reason why geared unis steer. (The torque arms is only on one side.)
If one side of the fork is turning, or maybe even bending some other way, I get that the wheel would pull off center. But I’m having trouble understanding* how the vertical up/down pull on the bearing mount bolts can cause the fork leg to turn or bend? Is this possibly a problem unique to “V” style frames, that might not affect use of a disc brake on a KH frame?
*I admit I’m no physicist, so it’s possible it’s just me that can’t get my head around this.
It has nothing to do with the vertical pull. The brake calipers are next to the d-brake, not aligned with it (and therefore not aligned with the frame). This means that when brake while going forwards, the lever on the d-brake is pulled both toward the frame let but also towards (I believe) the inside of the hub, so this would force the frame to pull to the left slightly.
I think I thought through that correctly…
I think disk break steer is real and not in your heads. The force is acted on only one side. Rim breaks have no steer since the force is equal (if adjusted properly) on both sides.
Roger - your veering w/ non disk breaks I bet is do to how you position yourself as you apply the breaks.
I constantly switch hands on the handle. I started doing this because one would get tired and I noticed in trials vids if one could hop equally well w/ either hand, to either side it would make some lines easier. So I switched often enough so I stay competent w/ either hand. It tends to vary, but right now drops are easier w/ my right hand and keeping the uni straight on climbs is easier w/ my left.
Oh, yah. good point Twente Muni
Sorry Ben, I guess you aren’t crazy 
UniShark, the torsion from the brake (I was wrong to think of it as a linear force) will slightly bend the frame leg in the for-aft direction. Twin-leged frames like the oregon and nightrider should be stiffer than single leg frame like a KH in this regard.
Try to see it this way:
The brake calliper is mounted on a horizontal arm that is fixed to the bottom of one fork leg. The braking force pulls the arm upwards, at the end of the arm. This causes the fork leg to bend backwards.
From construction viewpoint, the traingular shaped nimbus fork is better resistent to this bending then the single tube of a KH fork.
But only a stifness calculation or measurement will show what fork is stiffer with respect to the brake twisting.
Gosh, thanks so much Tom, I was beginning to worry 
Seriously though, it’s not a big deal and I have learned to compensate when I pull the brake, I angle my hand slightly to the right so I’m resisting against the direction of pull.
I like disc brakles, they make me happy.
The big question: What will Bryce do with all his free time?
I got it, he can make grab handles!!
So, any stealth Nimbus frame pics??
any one want to buy me a new hub does anyone now how strong they will be?
Thanks all, I finally get it. Seems like a pretty minor issue, not enough that it will affect my (already made) purchasing decision, but definitely an interesting discussion.
My main problem with Nimbus right now is that with all the new goodies coming out, I’m sure to get in trouble with the boss (read: wife) spending money on it, before I can actually ride, and while still paying off uni-related medical bills.
I had some problems when an outward spoke broke on the side of
the disc brake. I did not want to remove the disc and the bearing,
so I fiddled the spoke through the hole of the disc and back. It came
out somewhat twisted, but its seems to work.
Is there a better way to change a spoke on the disc side?
Looks to be a lot of braking stress might be placed on the bearing holder bolts.
Is it a problem? I’ve stripped a couple of KH frame bolts (on the brake mount), so it’s pretty soft material.
Okay, for the folks who have not used the bearing cap caliper mount:
The side of the bearing cap proximal to the caliper hanger is tightened until it is flush with the frame side bearing holder, then the other side of the bearing is used to tighten down the cap onto the bearing.
Would they strip out? Hmmm, I don’t think so, but then I’ve never stripped the frame threads. The bearing holder threads are burlier than the magura threads, I can’t imagine that the brake mount is going to apply that more stress to the cap, the caps are already getting quite a work out. If they due strip, then I’d use a longer bolt and a lock nut/washer.
A though just occurred to me: Why aren’t the bearing cap bolts oriented facing down? Then if the threads were to get stripped, it would be in the caps, which are replaceable.
[QUOTE)
It makes sense, that’s probably why UDC went to that mount, no welding, no mistakes, works with every uni, and it works on both sides.
Ben, think about this statement… How can it work on both sides? The disc can only mount to one side of the hub, and the recessed bolt holes are one side dominant, so it can only mount one way. UDC went to this mount sure, and Mountainuni proofed the concept over a year ago with an eerily similar design. We’re all into disc adoption, been riding disc for 2+ yrs now, as have many early adopters. I’d let Roger answer the works with every uni statement. We’ve discussed the challenges with a ubiquitous design, nonKH bearing cap bolt patterns, crank stop widths, etc.. I think the design is very cool, and if you want a new build from scratch, and you understand how to build a dished wheel, with different length spokes, and not compromising strength. Its not as easy as pitched.
Disc brakes do seem to have a tendency to pull to the side, it’s subtle, anyone else notice this?[/QUOTE]
Conceptually, There may be some Very subtle brake pull, but I have discs on all size wheels 24-36 and can only sense that on the smaller wheels and in extended braking scenarios. Funny how these are even out yet, but the experts are already chiming in with disc brake reviews 
Sorry for the thread jack, theres room for all to play here.
This new ready-for-disc-brake-hub will be a standard hub in every new offered nimbus muni?
Replacing spokes on disc side of hub:To replace the spokes on the disc side of the hub, you need to remove the disc and bearing.
Mounting of the d’brake mount:The d’brake has an offset top surface unlike other bearing mounts. The side where the calliper mounts locks down tight to the frame. This gives the calliper a better mount, less potential movement and causes less stress on the components.
Mounting the d’brake on different frames:The brake mount is slotted and has been tested on them all (even the pressed steel - but don’t recommend these) and works with them all. The mount is sided as it has recessed holes; since the internal disc’s are mounted on the inside on the left and external ones are on the right, this does not matter.
Release of Kris’s disc brake system I will leave Kris say more of his brake system, what I can say is that the d’brake has been tested with it and is compatible. As far as I know Kris is not releasing a bearing cap mount for his system.
Will the discbrake be fitted to all Nimbus Muni?No. The brake can be fitted to any of the Nimbus Muni… but there is going to be a new range of aluminium framed Muni with the break already fitted. The Oracle.
Umm, so the hub can only be mounted facing one direction? You might want to rethink that on
Trust me, it’ll work on both sides, might take some spacers and such.
It is actually the international standard that says it should be on that side. The callipers are designed that way around. You can use the hub on the other side… but you would have to use a calliper designed for duel disc, but these are to say the least, uncommon. The alternative is to use the hub/brake reversed, but he calliper would be out the front.
It is worth saying that since we have followed the industry standard for disc brakes, all callipers and mounts will fit on the disc and brake. They are all made to fit within a dimentional criteria and we have built the system around that.
Roger
Excellent! 
I’ve never noticed it pull to the side and I drag the disc brake on my 36" Impulse down every hill because I’ve got short cranks and old knees. Of course, now that I have read about it, I’m sure I will start to notice it and it will probably drive me crazy. Thanks a lot! For the record, I use Magura rim brakes on my 36" KH Schlumpf and I can barely tell the difference. It’s more of a low maintenance issue (changing disc brake pads was easy) for me. I’m no mechanic.
I’ll buy the first 26" Oracle off the UDC container. I like the sound of an aluminum frame. I plan to use an Ardent 2.4" tire to keep the weight down. Nimbus almost had me with the Oregon but it was too tall (might as well ride a 29er) and heavy for my liking. I really wanted another 24" MUni but limited tire choices (even the 3" Duro is more volume than I need for the XC trails in my area) did me in. The Oracle sounds just right. I can’t wait!
I’ll have the second hub and d’brake then!