Damn, this thread comes along after I spent hours fiddling, trying to get mine to work just right. oh well, the proper set-up has been covered, and damn do they work well when set up right.

the really nifty cunningham bikes have an integrated mud shield to guard these (strangely placed) brakes. I have heard tell that the chain-stay mount is to avoid over-flexing the weaker seat-stays, and I could believe it. I'm not saying I do, but it sounds kinda plausible.