on 10/5/09 7:37 AM, GeorgeS at chobur...@gmail.com wrote: > Until recently I had never had a bike with cantilever brakes so I am > coming to the subject with almost total ignorance. I mounted a set of > IRD Cafam brakes that I got from RBW on a new Surly. The levers are > Shimano Tiagra. My problem is with the front brake. When the > straddle cable is adjusted so that the brakes come in contact with the > rim before the levers bottom out (about 3/4, feels OK), the left brake > arm (left as I'm facing the brake) does not retract away from the rim > when I release the lever. With no pressure on the lever, the brake > stays in contact with the rim. The right arm pops away from the rim > like it should. I can correct this by adjusting the straddle cable > but then the levers bottom out and I don't feel I've got enough > pressure on the rim to stop when I'm riding fast. Suggestions? I've > thought of changing the spring tension on the left side (now the > spring is in the middle hole) but I wanted to get advice before I went > that route. My sense is that the left brake is not pivoting on the > post as it should. What about giving the inside of the cantilever > hole some polishing with a dremel? Thanks.
You might take a look at that canti post. There may be paint on it, or the end of it could have been peened by overtorquing (not common on a new frame). I don't know why adjusting the straddle cable would fix the issue, unless you still have tension in the cable run, and that's keeping it tight. Or, you are running such a short straddle that the brake arms are well past vertical when pads are in contact with the rims. First - I'd repeat the mantra - "AASHTA" and read this: http://sheldonbrown.com/cantilever-geometry.html and http://sheldonbrown.com/canti-trad.html I thought the IRD's had a screw tension adjust on the springs, so you might give that a half turn or two before you switch holes. FWIW, I usually end up using the highest return spring tension (i.e. the third hole) setting. I would also double-check that you have a clean cable run - make sure the cable is seated properly in the lever and that the housing is firmly against the brake lever body. Any sharp turns in the run? Particularly when it goes into the brake hanger... Check the adjuster (and cable housing ends) for any burrs, also. >From your description, I'd tend to suspect the straddle cable setup. You should be able to change the pad position by swapping the washers, and that might let you change the straddle cable. But, I'd follow the other points as well. Hope that helps. - Jim -- Jim Edgar cyclofi...@earthlink.net Cyclofiend Bicycle Photo Galleries - http://www.cyclofiend.com Current Classics - Cross Bikes Singlespeed - Working Bikes Send In Your Photos! - Here's how: http://www.cyclofiend.com/guidelines "There were messengers who named their bikes, but Chevette never would have done that, and somehow because she did think about it like it was something alive." William Gibson - "Virtual Light" --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bunch@googlegroups.com To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en -~----------~----~----~----~------~----~------~--~---
