Shimano Disc Brake Adapters make it possible to run 74mm post mount disc calipers on frames and forks with 51mm ISO tabs. Front 74mm Post Brake to 51mm ISO Frame – 160mm Rotor F160PS Manufacturer part ISMMAF160PSA Front 74mm Post Brake to 51mm ISO Frame – 180mm Rotor F180PS Manufacturer part ISMMAF180PSA Rear 74mm Post Brake to 51mm ISO Frame – 160mm Rotor R160PS Manufacturer part ISMMAR160PSA Rear 74mm Post Brake to 51mm ISO Frame – 180mm Rotor R180PS Manufacturer part ISMMAR180PSA