Classic & Vintage - Cantilever bosses with backwards spring notches?

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Snordalisk
05-06-07, 06:09 PM
I posted this over in the Mechanics forum, but I figured I might have better luck at C&V given the age of the frame.


I've just started work on a Shogun Prairie Breaker II mountain frame of unknown vintage, it's got really laid back geometry and Tange MTB tubing, if that helps determine anything.

It has what at first glance seem like roller cam bosses with the spring notches outboard, but they're located below the rim like cantilever bosses. No brakes came on the frame, and it's unknown whether it was a warranty replacement or not, so it could even be defective.

Anyone have any ideas as to what I can use for a rear brake on this? I tried some current stock cantilevers but the spring really (really) didn't take kindly to being bent that far around. I'm willing to do some crazy modifications if necessary.

There isn't any brake I know of that fits ALL of these characteristics, chainstay mounted bosses below the rim, with outboard spring notches rather than the usual inboard. What the heck do I have here?

I'd really like to complete this project, has anyone seen this before?


Snordalisk
05-06-07, 06:41 PM
I just consulted an old copy of Barnett's, which states:


"If the spring hole in the braze-on is outboard of the stud, a special spring is required. For Shimano cantilevers, this spring will be square wire rather than round."

I'm bracing myself for the task of digging through a dozen parts boxes that might contain that "special spring", at least I know it exists now.

Sorry for the diversion, please go about your business.