Originally Posted by
wroomwroomoops
Pretty much every bike frame and fork that is disc-brake compatible has "51 mm International Standard" also known as simply "IS mounts".
Sort of, the IS mount is now just about obsolete for forks, with the post mount now the standard fitting; for the frame, post mounts are becoming more common, too early to tell if this will supersede the rear IS mount as well.
Disc brakes haven't been available for several years with IS mounts, all are now sold as Post Mounts, with IS adaptors.