Q: I have an ’87 Peugeot with old Shimano BioPace chainrings. Low gear is 42×24-tooth. My buddies with triples are killing me on climbs! Should I ditch the BioPace and install 53/39-tooth rings? — Byron M.
COACH FRED: Ditching BioPace chainrings is an excellent idea. That out-of-round design was an experiment that failed. No studies that I’m aware of showed any advantage, aconclusion that has been proved empirically because they’re no longer manufactured.
Switching to 53/39-tooth chainrings will give you a lower climbing gear, but you might also look into a wider-range set of cogs. I assume that your ’87 bike has a 7-speed freewheel. They’re still available. A 12-26-tooth freewheel would give you a 39×26 low gear. That should let you spin with your buddies on most climbs.
It works for me, and there are studies, e.g. http://blog.artscyclery.com/general/shimanos-ill-fated-biopace-validated-in-university-study/