Cyclocross - Conversion from 27" to 700c with cantis aint so easy

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thenomad
04-04-11, 09:50 AM
Having trouble getting this older frame to work just right.
I'll try reshaping the brake pads a touch and it might work. Discovered the canti studs are closer spaced so it's giving me more fits than I thought.


Cynikal
04-04-11, 10:00 AM
Older touring bikes have their canti studs closer together than the modern standard. I ran into the same issue converting a 85' Nishiki Cresta to 700's. I could never get good braking out of it without using 90's MTB canti brakes. They much more adjustability. This was a vintage build so I wanted to use the original wide profile brakes so I ended building some 27" wheels. Now everything is as it should be.

Long story short, try some 90's MTB cantis.

thenomad
04-04-11, 11:05 AM
I've got some Anza that I'm using and looks like it may all fit together with some pad shaving and such.


meanwhile
04-04-11, 11:13 AM
Don't Pauls make a weird type of canti that will adjust for anything between a 26er and 700c on the same frame??? It probably costs as much as a frame, but -

http://www.paulcomp.com/motolite.html

A polished collar fits around the arms and holds the Kool-Stop brake pads in place, while allowing them to be finely tuned for height and toe-in...

http://www.paulcomp.com/images/motolitemain.png

Hmm... List price is $125 a wheel. Which is more of an ouch than a hmm, really.

thenomad
04-04-11, 01:02 PM
those look like adjustable V brakes. I have anza brakes that look very similar to that but are true centerpull cantis. The mounta slides up and down the post. It's looking like it'll work but the pads will have to be slightly shaved to avoid any wierd tire contact.

GrayJay
04-04-11, 05:47 PM
Dont overlook the possibility of re-locating the canti-studs to correct height/width for your brakes and wheels. I recently converted an old road bike from sidepull to cantilever brakes and it was very minimal work or cost to add the canti-studs. (but this does mess up any underlying paint or chrome). I brazed the post on myself, total cost for the studs was around $5 from NOVA.

thenomad
04-04-11, 08:13 PM
what brazing method did you use?

GrayJay
04-05-11, 01:41 PM
what brazing method did you use?

I used Oxy/acetalene torch and brass brazing rod. I was more worried about achieving a really strong braze fillet attachment for the cantilever lugs than about keeping temperature low with expen$ive silver braze rod (which doesnt fillet as well eithor). I have done plenty of welding on automotive fabrication projects but this was the first time I have turned the torch on one of my bikes. I read all the framebuilder tips on brazing, got some 1/16" low-fuming brass rod and flux that seemed to melt and fillet on the tubes much easier than the 1/8" rod I already had. I was carefull not to overheat the steel, just got things hot enough to flow the brass. At the same time I also added a buch of new cable stops to better suit CX cables/routing, added a pump holder peg, chain holder peg and replaced the damaged seatpost binder. Vast majority of the time spent on the project involved using small files to shape the parts for a precise fit and to clean up the brass fillets after the torch work. THe file metal shaping work was intricate but degree of control you can achive shaping metal is impressive and rewarding. I will shoot some pictures and document before I shoot the bike with paint.

thenomad
04-05-11, 04:16 PM
cool, how much did that run you? obviously you must have had a bunch of stuff on hand from auto work

GrayJay
04-05-11, 04:34 PM
All the small braze-on parts are rediculously cheap
http://www.cycle-frames.com/bicycle-frame-tubing/STEEL-SMALL-PARTS

I probably have less than $30 into upgrading the frame (if you dont count existing tools and my time).

thenomad
04-05-11, 07:59 PM
Had some trick old cantis from Onza and after swapping springs they are definitely going to do it. I wish I could slap these on my other bike and go 700c but we'll see how the older dia compes do on it for cross season.