Biopace chainrings are kind to this old man's knees, so I'm always on the lookout for them. I just aquired a crankset with a 130BCD 52/40. I always thought that 42t was the smallest 130BCD Biopace ring. So my questions are these:
1) Just what sizes DID Shimano make these in? In 130BCD I'm aware of 53, 52, 42, and 40T, in 110BCD 50, 48, 44, 40, 38, and 36T, in 74BCD 28 and 26T.
2) I'm not the only one beating the bushed for these things. What are the chances of Shimano (or an aftermarket producer like Vulta) doing a new production run?