A week ago I was tipped off by a list member to LOOSE SCREWS offering of 0.6 mm chainring spacers at 1.2 mm and 2.0 mm. This was to solve the problem of the chain rubbing against the large chainring when the chain is on the small chainring and the 2nd smallest cog in the rear. I purchased the 0,6 spacer set and did some research. It turns out that most chainrings are offset so that if you place them on a flat table you can measure the offset on one side vs. the other, based on the distance the teeth are spaced away from the table top. I flipped the inner chainring around and added one 0.6 mm spacer for a total of 1.3 mm increased distance between the big chainring and the small. This in turn cured the annoying chain "ringing sound" that I could hear when on the smallest cogs. I always thought that chainrings should be set up so that the stamped number always appears to the outside or away from the frame, for both large and small rings. This, evidently is not the case. Perhaps other brands of classic and replacement rings also have a subtle offset. This allows us to fine tune chainline in effect, and also to cure "the dreaded chainring ringing".
Garth Libre in Miami Fl. USA North America