Buy Shimano Lock Ring Centerlock SM-RT81 at HBS

Shimano Deore XT SM-RT81-S Disc Brake Rotor - 160mm, Center Lock, Silver/Black

Shimano Center Lock Disc Brake Rotor -For XT /Ultegra

Shimano SM-RT81 Rotor Lockring (Internal Spline Type) - Rebec and Kroes Cycle & Sport

Wolf Tooth CenterLock Rotor External Splined Lockrings for securing centerlock rotors to centerlock hubs. Machined from 7075-T6 aluminum at Wolf Tooth in Minnesota, USA. Compatible with 12mm, 15mm and 20mm thru axles and QR. Machined 7075-T6 aluminum. Durable anodized finish. Torque to 40Nm. Not compatible with 6-bolt rotors and hubs. Washer included.

Wolf Tooth Centerlock Rotor Lockring - Gold

Hands On Bike: Avanti Inc 3: Shimano RT81 Ice-Tech Centerlock Rotors

Shimano Centerlock SM-RT81 Lock ring - Mantel

Shimano Disc Brake Rotor Small Parts Centerlock lock rings Original Shimano parts guarantee that all components work perfectly for optimum performance and maximum safety and longevity.

Shimano XT SM RT81 Disc Brake Rotor Lock Ring and Washer

Wolf Tooth Centerlock Rotor Lockring - Gold

It provides even pressure across the disc rotor so it's less likely to warp due to uneven torque and it's simply faster and easier to install and remove. The XT M8010 Centerlock Rotor Lockring is perfect to keep in the toolbox just in case you might need it on a trip. The lockring is compatible with 12 15 and 20mm axles and Centerlock rotors and requires an external BB tool to torque the lockring to the hub.