Yes, CR720's can have a little bit of play on the posts, as will many cantilever brakes, and yes, generally higher-end brakes have closer tolerances. I once heard a story, probably from Paul Brodek on this list or iBOB, about Charlie Cunningham. When he was licensing his Roller-Cam brake (considered by many to be the ne plus ultra of rim brakes), he was showing the SunTour engineers the proper installation procedure and got out his jeweler's files to file down the brake posts on the frame so they fit the bushings on his brakes just so. The SunTour guys were looking askance at each other because they could never imagine assemblers in the big Japanese or Taiwanese factories doing the same thing.
All that aside, in my experience the amount of play demonstrated by a brake arm on the pivot isn't the primary cause of juddering or squealing. Juddering is often associated with relatively flexible forks: as the fork flexes back and forth under braking, it effectively changes the distance from the housing stop (usually in the upper headset assembly) to the straddle cable and thus varies the braking force up and down, producing the juddering. Many on this list and elsewhere have had good luck switching to a fork-crown mounted housing stop like this to address juddering issues: https://www.amazon.com/Tektro-Front-Cable-Hanger-Black/dp/B006GHDRYC Since this drastically reduces the distance between stop and straddle cable, it reduces the variation in length associated with flex, and thus, hopefully, the judder as well. In my experience, if you are thinking about it anyways, adding a front rack like a Mark's or Mini Front also stiffens up the fork around the brakes and can reduce judder. On Tuesday, January 23, 2018 at 7:19:13 AM UTC-8, Michael Cinibulk wrote: > > I have a first generation canti Sam and my CR720s wiggle quite s bit in > the pivots, more so on the fork. With more than usual toe-in they perform > just fine. Still as the toe-in lessens with pad wear the judder starts to > reappear. Do others have this issue? Are the tolerances of the 720s just > poor? Are other brakes better in this regard? I guess I could swap in the > ‘90’s vintage Deore LX brakes on my tandem to check. I assume that brakes > with built-in pivots like Paul’s would be an improvement in the regard. > Comments? > > Mike Cinibulk > Bellbrook OH -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
