deadlytreddly

Has anyone experience (or understands the theory involved) in adding cantilever bosses / pivot points to an old 531 frame and fork currently equipped for Calipers? The aim is to facilitate a conversion from 27' to 700c and allow for modern brakes and wider tyres to be used for loaded touring. I have some specific questions:
Is there a risk of somehow weakening the fork or the rear stay through the braze-on process?
Once done, will this result in different forces being placed upon the fork and frame when braking, which might lead to complications/weakening/failure?
Is it preferable to swap the fork with a new fork equipped with cantilever mounts (eg. surly) and keep calipers at the rear?
Thank you.

Dr.Deltron

Adding canti bosses only weakens the frame/fork if you don't know how to braze.
Otherwise it should be fine.
I sometimes braze on canti bosses, or downtube shifter bosses to replace clamp-on types, or BB cable guides to replace clamp-ons, and replace rusty cable guides/stops.
But I've been welding since the 7th grade, and I have a torch. Plus, when I'm done brazing, I repaint the whole frame...DUH! That IS one of my main occupations.
Always cracks me up though, when someone hacksaws off downtube shifter bosses. All you gotta do is add some heat to soften the brass/silver and it pops right off, clean as a whistle!
NOTE; road bike forks are sometimes too narrow to add canti bosses to. They will not be far enough apart for the brake to set-up properly.
Good luck with that! Pictures of the results!

HillRider

I would also add that road forks may not be wide enough for fat tires even if the brakes clear them. Measure between the fork blades near the crown to see how much room you have to work with.

frameteam2003

Bosses were often added to french touring bike as they make the brakes more positive.Would be a plus to your touring bike if the fork has the room you want.

jim-bob

I can second this part - my 3rensho fork is narrow enough that the line between slack cable and rubbing pads is very very fine.

nlerner

Going with long-reach centerpull brakes is another easier way to convert from 27" to 700c and have clearance for fenders. Dia Compe 750s or Mafac Raids will give you more than enough reach.

Neal

cyclotoine

You can also use those horseshoe things that reduce flex.

deadlytreddly

Thank you for your respsonses. Very helpful. I don't yet have the bike so have been unable to measure the clearance. It is a '79 Dawes Galaxy. What would be the minimum width for effective canti operation?