Wilwood has been making small changes and improving their inboard rotor mounts, and they’re as good as you’ll find now. The design is really good for performance of the rotor. It helps the rotor to run freely whether it’s hot or cold. This also helps to keep the rotor from cracking during it’s heat cycles. The mount clamps tight on the axle so you don't have to worry about any spacers. We have the rotor mounts in stock to fit standard 8 bolt rotors or smaller 6 bolt rotors