Formula Center Lock Rotor Lockring Locking It Down If you're using centerlock rotors on your hubs, then you'll need centerlock lockrings to keep them tight. The Formula Center Lock Rotor Lockring is a lightweight lockring that is designed to work with centerlock rotors. Weighing in at only 9g, you'll barely even know it was there. Features Designed for centerlock rotors Weight: 9g Manufacturer's part number: FD-G045-34 | Formula | Center Lock Rotor Lockring Black