Would it be possible to mount a caliper brake through the crown of the Nimbus 36" frame (as seen with a standard frame in Uni Mag Issue 1)? I can’t tell from the picture if there’s enough room below that back tubing. link
i would love to run one too because i’m too cheap to get a magura.
You certainly couldn’t get one behind the frame, you might be able to mount one on the front of the frame if you drill the hole really low so the bolt doesn’t interfere with the rear bracing.
I think it is, cause i’m doing it soon to my coker. 
Doesn’t look so judging from the picture at least, perhaps on the front (as someone already pointed out).
May i ask why - because you want a drag brake?
In that case wouldn’t V-brake + Magura to V converter (from a trials shop) + “normal dragbrake setup with shifter” work? (Of course this would cost a bit more, but on the positive side, you don’t have to put a drill to your new frame!)
I don’t know if there is a big ratio difference from road/bmx brake to a V-brake, that could cause problems (or perhaps it would be even better) though.
i think UDC sells some brake adapters
http://www.unicycle.co.uk/shop/shopdisplayproduct.asp?catalogid=909
isnt that wat u are looking for?
i’m not sure how these things work… but might be it 
Sadly, No.
That was one of the first things I looked at when I got mine. I bought a BMX style caliper brake from eBay after reading the article you’re refering to, with the intention of fitting it to my 29er. It was only when it arrive that I realised it was a back brake, and the bolt wasn’t long enough for the thicker tube at the crown of my 29.
So, looking at the rear brace of the new Nimbus, I thought it would work a treat. Sadly though, the distance between the brace and the wheel rim is about 1/2 - 3/4" too far.
As Kington99 says, it should work on the bottom of the main tube though (if it’s a front brake not a rear one!), but I think the mechanism would have to go at the front rather than the rear.
I’m keeping my eyes open for cheap Maguars on eBay now though 
STM
A few interesting things to note for purposes of a caliper brake install.
First, the main (seat) tube on that frame is an external butt, with much greater wall thickness than the higher section of the tube. Thus drilling a fore/aft hole in the lower section to mount a caliper brake will not weaken the tube.
Second, Roger has apparently positioned the main (seat) tube such that the legs (downtubes) are welded to it at a more forward point on the sides of the tube. So indeed there is more room at the back of this tube for caliper style brake shoes to not hit the downtubes.
Third, make sure the width of a caliper brake and its cable stop will not interfere with your legs while pedalling. Otherwise, this frame looks very useful for a caliper style brake.
Fourth, on all my rim brakes, I grind off about half of the brake shoe area, thus making the brake shoes less effective and grabby on the rim.
Pete
I don’t want Maguras or anything too complicated/expensive because I hardly ever use the brake anway. Here’s a couple pictures of what I’ve got now. I’m hoping to replicate it on the Nimbus frame. It’s an Odyssey 1999 BMX brake drilled through the seat tube. It came with 2 bolts, one short and one long. I think I’m using the longer one. The brake pads are not too grabby at all, which is nice. I’m thinking it will work if I mount it on the front of the frame as suggested.
To be honest, bearing in mind the magura mounts are already in place, maguras are probably simpler to fit than anything else. The set I have on my nimbus 36 i got for £10.50 on ebay, and I spent another £8 on new pads and a tpi dial. The set on my muni i got got for £22 on ebay and were usable straight out the box. There are currently sets on ebay starting at £1.
Have you got a link? Every time I’ve checked eBay all the stuff due to finish in the next day or two is at least £40.
(Yes, I know it seems I’m being lazy not looking now, but I can’t use eBay whilst at work, so will have a look tonight as well)
STM
Thanks. I’ll have a butchers when I get home tonight.
STM
Would you say there’s enough clearence for the brake to be used on a 24 x 2.6 tire? Also, could you take a picture of how you set up the brake lever?
Not sure. It would be a tight fit if it did. The pads are far enough apart for pretty much any rim (the tire can be deflated to pass between the pads), but the knobs of your tire might rub the lower part of the brake arms. I did a quick test on my 2.5" trials tire and it seemed pretty close to the limit. The brake lever is mounted to the left handle of my T7. Others have recently posted pictures of that setup… mine looks the same.
I was able to drill through my Nimbus 36 at the crown to get my caliper brake mounted:
It doesn’t seem to have structurally compromised the frame at all, so I think that’s a pretty good deal. I considered putting it on the rear brace like the above poster, but I thought it’d compromise the frame too much there. Guess I was wrong :). It works either way, I guess. However you want to crack it!