I've used the Tektro R559 brakes on a 27" to 700c conversion for an
older Schwinn Paramount (Chicago era) P-15 bicycle. I'm very pleased
with their performance, and the aesthetics of a Tektro sidepull are
much nicer (IMO) than using some of the long-reach centerpull brakes
(e.g. Dia-Compe 750, for example). Here's a photo of the Tektro R559
brakes mounted on the bike:
http://www.flickr.com/photos/37964304@N05/4881013568/in/photostream
I would have preferred, partially from a loyalty to Rivendell, to use
the Silver brakes. They weren't, however, available in a bolt-on
version which I needed for this older bike.
Jim Cloud
Tucson, AZ