Absolute Black makes a lot of claims on their website as to the advantages of their oval chainrings and while you might not buy into it, I know people who use them and swear by the technology. New to Absolute Black are these 110/4 BCD chainrings, designed specifically for Dura-Ace 9000, Ultegra 6800, 105- 5800 and others. See more at Absolute Black.