I had Biopace on my last touring bike. I remember when everyone worked out that Shimano had them designed wrong & rotated them. Didnt make any difference to me, I hated them. Probably didnt help that only the outer was Biopace. The other two rings were roundInterestingly, Shimano set their high-effort zone at the 'dead spot' , while Rotor and other companies set the low-effort zone at the 'dead spot'.
For what it's worth, I still have a set of used (not by me) biopace chainrings inner and outer for experiments.I think its worth a revisit. I'm thinking to conduct several on the road tests with 3 rings - ROTOR, BIOPACE and ROUND. TT TEST, HC TEST and ROULER TEST. The protocol is very simple - I'll use a PT Wheel for data aquisition , then compare results of power vs. time.
Correct me if I'm wrong: Does an elliptic chain ring not result in a variable amount of chain slack that has to be picked up by a rear derailleur? A simple cog at the rear as in an internally geared hub or single speed or fixed gear would not do that. So I seriously doubt this would work with an Alfine.Plan B is to use it single chainring with an Alfine hub in the back.