Two rotor mounting standards dominate the disc brake world: Shimano's Center Lock system and the older 6-bolt pattern. If you've got Center Lock hubs but want to run a 6-bolt rotor—maybe you found a deal on rotors, maybe you prefer a specific brake track design, or maybe you're just using what's available—the Shimano SM-RTAD05 Disc Rotor Adapter bridges that gap. The adapter mounts to your Center Lock hub splines and provides the standard 6-bolt mounting holes, letting you install conventional rotors on Shimano's proprietary hub interface.

The adapter installs using the same external lockring tool you'd use for a standard Center Lock rotor or a Hollowtech II bottom bracket cup. It threads onto the hub's Center Lock splines and torques down to secure both the adapter and the rotor as a unit. The design includes an anti-loosening plate that prevents the assembly from backing off under repeated braking loads—important since you're adding an interface between the hub and the rotor that wouldn't exist with a native Center Lock setup.

One compatibility note worth knowing before you order: the SM-RTAD05 doesn't work with 2-piece rotors that have aluminum spiders, like Shimano's own RT86 and RT76 6-bolt rotors. Those designs use a different bolt pattern spacing or offset that doesn't align with this adapter. Standard 1-piece steel rotors in the 6-bolt pattern work without issue. The adapter supports rotor sizes from 160mm up to 203mm, covering everything from road and cross applications through trail and enduro builds.... Read More