Brand x disc brake adaptor is to post this quality precision made brand x disc brake adaptor converts a 51mm international standard is frame mount to a 74mm post mount to suit your brake rotor size available sizes is to rear post 160mm is to rear post 183mmfront post 203mm is to rear post 140mmfront post 160mm is to rear post 160mmfront post 180mm is to rear post 180mmfront post 200mmfeatures lightweight precision made alloy adaptors mounting hardware bolts are not included compatib