thumb|right|Biopace triple crankset, a non-round crankset thumb|right|The Biopace logo on a chainring Biopace is a tradename for a type of ovoid bicycle chain ring manufactured by Shimano from 1983 to 1993 The design was intended to help overcome the "dead zone" where the crank arms are vertical and riders have little mechanical advantage.
thumb|right|Biopace triple crankset, a non-round crankset thumb|right|The Biopace logo on a chainring Biopace is a tradename for a type of ovoid bicycle chain ring manufactured by Shimano from 1983 to 1993 The design was intended to help overcome the "dead zone" where the crank arms are vertical and riders have little mechanical advantage.
Biopace chainrings have a reduced chainring diameter coinciding with the cranks being horizontal. This is supposed to smooth the pedaling action, allowing the rider's feet to carry more momentum through the power stroke, and having it smoothly removed at the bottom of the stroke rather than encouraging riders to push bigger gears and risk knee damage due to higher knee joint loadings.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).