Rotor Goes Back to the Future with Ovalized Chainrings

No, Rotor claims its product is completely different from the gone but not forgotten Biopace chainrings. A decade ago, they debuted courtesy of Shimano but didn’t last.
Rotor QXL chainrings offer 16% ovalization. Rotor claims to offer a different technology compared to the old Shimano Biopace system. - Photo Bike Europe