Hey all,
Well, this is more of an emergency/daily rider solution. I've only had two sets of Stronglight 93s (both with original rings), one with a 42/52 combo that worked perfectly with a Shimano HG chain, however, the other, a 45/52 (I think), with its original Sedis chain, flopped happily right between the rings each time I shifted. Upon further inspection, it appeared that the chain had gotten caught in between in the past and someone had kept on riding with the chain like that (the grooves from the chain pins were deep and ugly between the rings) and it had bent them so bad that the rings had cupped outward. The smaller 42t ring seemed to have taken the worst of it so I just flipped it over and put it on backwards. Of course, not the best solution since I lost the luxury of the recess for the chainring bolts, but the problem was solved and it shifted and performed fine after that.
I wonder if this problem is related to the chainring sizes being closer to one another?
Cheers,
Paul Grens
Chicago, IL, U.S.A.