Originally Posted by
dabac
AFAIK center-pull is a type of caliper brake, and doesn't use frame/fork mounted brake bosses.
Canti- and v-brakes generally use the same brake boss spacing, with some old frames/forks/brakes using a tighter spacing.
Then there is the U-brake. Generally found on BMXes and a handful of MTBs.
I guess it's this you're asking about. Unfortunately I can't help you there.
Almost all true. What you call centerpulls also can be found mounted onto brazed on bosses, much like "U" brakes and Roller Cams but with some boss dimension and spring attachment differences. Usually found on hand crafted frames of many years ago or more recently among the rando crowd.
Tom- Back in the early days of mountain biking Moots made a few bikes with moveable bosses, they were brazed onto surround clamps that could slide up and down the blades or stays as needed with different wheel diameters. I ran some common numbers and I think you'll find the pads won't come close to contacting the 650 rims, even if the bosses are otherwise compatible and of a width which works (which they both are likely not). Andy