by istigatrice on Tue Oct 13, 2015 12:17 pm
Just thought I'd give this an update:
I pulled apart the RD cage today, and it was ever so slightly twisted (compared to a flat surface). I've twisted it back so that the screw holes for the jockey wheels sit flush with a straight surface.
What surprised me more was that the RD hanger was also twisted. I straightened this as well. Not sure how it would have gotten twisted, but obviously contributed to the problem.
I tested a few downshifts, which worked fine... a few of them looked like they were about to drop the chain, but it righted itself almost instantly - if I wasn't looking right at the jockey wheel I wouldn't have noticed. Time on the road will tell if I've fixed the problem.
Also, not sure if this affects the problem, but I also had to tighten the b screw even further. to prevent the jockey wheel from rubbing on the cassette after the straightening.
Finally, I also tried to get a measurement of the chainline, but I didn't have tools to do this accurately (a see through ruler isn't the best tool on a black bike). I was getting a chainline of between 44mm with an uncertainty of 1mm, which is within error to what sheldon suggests with 43.5mm.
I write the weightweenies blog, hope you like it
Disclosure: I'm sponsored by Velocite, but I do give my honest opinion about them (I'm endorsed to race their bikes, not say nice things about them)