Whether you're in paradoxical possession of post-mount brake calipers and a flat-mount frame or just need to correct flat-to-flat mount adapter to fit your chosen rotor size, Shimano has a Flat Mount Disc Brake Adapter to get you up and running (and stopping) in a flash. Available in a variety of post/flat and flat/flat combinations to accommodate 140mm and/or 160mm rotors, this adapter installs quickly and ensures your calipers work seamlessly with that shiny new frame.