I am currently restoring an '85 Nishiki Cresta GT and I pulled the Cycloid rings off as quickly as I could. I even tried to sell them to my local bicycle co-op (which is what I do with any parts that I have no use for) and they found them novel, holding them up to the light and commenting, loudly, on their oddity. After their trip down memory lane, they tossed them back in my pile and stayed far, far away from them. I am replacing mine with regular, round Sugino rings (as soon as I can find some for a fair price).