Shimano Disc Brake Adapter
Depending on what size rotor you use, you will need a brake adapter to properly space your disc brake caliper.
There are two standards for disc brake mounts: IS: 51mm International Standard, PM: 74mm Post Mount
SM-MA90 series brackets are specifically designed for the new generation XTR-M985/988 disc brakes but can be used on all Shimano 74mm-caliper brakes
Mounting Hardware Included.