Originally Posted by Panthers007
A picture would help your query. Or three. I can't visualize what these look like.
Here is a factory built Peugeot PY10-CP from 1979 with this feature.
This was the very same setup which Bernard Thevenet used when he won the Tour De France on his Peugeot in 1977. This commercially available consumer model had to be ordered through a Peugeot dealer. They were then built on order in the same small department which built the actual team racing bikes.
Peter Weigle now custom builds similar bikes... but his bikes and fittings are of course MUCH
better than any others ever produced... Here is an example on one of his recently completed bikes (2009)
This shows a Mafac "competition" brake mounted onto a custom made post. These posts are produced for him by another enthusiast/machinist and are hand brazed onto the seat stays. ... Notice also the small "tunnel" above the post which anchors the end of the spring. This tiny piece is also brazed directly onto the frame and of course everything is carefully filed and sanded before painting the frame.
The original Mafacs used for this application were supplied to Peugeot with a simple alloy bracket which would seat onto the base of a d-shaped post... Weigle's version goes one step further and makes a super clean installation.
Here are some exact reproductions of the original Mafac studs with the spring anchor brackets (also custom made now, and by the same machinist):
If you analyze the first two photos, you can see that ANY center-pull caliper is/was essentially another variation of the classic cantilever-style brake... But, a central "yoke" was always used for easier (and much cheaper) mounting by fitting it to the existing holes bored through a standard bike frame's bridge and fork. Without the need for canti-style posts to be carefully located and brazed-on, this was a great time and labor saving expedient for a manufacturer. So, cantilevers were gradually omitted from most production French touring bikes during the 1960s.
Center-pulls really were among the strongest gripping brakes used for production bikes in their day [1950s through 70s]... Rivendell recognized their efficiency and they currently offer the last remaining version -still manufactured by Dia-Compe - 60 years after the same basic model was introduced by Weinmann.
When you think of the braking power of modern Dual-Pivot side-pull brakes, consider that the center-pull brake caliper ALSO utilizes the dual-pivot principle... in it's most raw and direct form.
I don't own a bike with braze-on center-pull posts... but I would definitely LOVE to have one built... maybe someday