Use this adapter to mount Hayes 74mm post-mount disc brakes to frames and forks which have 51mm International Standard disc mounts. Confused by the process of mounting Hayes brakes on your bike? Give us an e-mail [email protected] or call us at 800-577-8720 and well walk you through it! | Hayes Adapter - 74mm for 6" Rotors All I.S. Forks, 98-15068