The Shimano 105 FC-RS520 brings proven 12-speed road performance to your disc brake build. Featuring Hollowtech II spindle technology and a 50/34T compact double setup, it delivers smooth, reliable power transfer for road riders who demand quality without compromise.

Highlights

• 12-Speed Compatible: Works seamlessly with Shimano 12-speed HG road drivetrain components for smooth, precise shifting.
• Hollowtech II Spindle: Industry-proven two-piece crank design integrates the spindle into the right crank arm, reducing weight and improving stiffness.
• 110 Asymmetric BCD: Asymmetric 4-bolt chainring interface provides optimal chainring rigidity and allows for a wide range of chainring size options.
• Compact Double 50/34T: Versatile gear range suited to road riders seeking an accessible climbing gear alongside a strong top-end.
• Disc Brake Optimised: Engineered specifically for modern disc brake road frames with 135/142mm rear axle spacing and 415mm+ chainstay length.
• 44.5mm Chainline: Optimised chainline for efficient power transfer and reduced drivetrain wear across the cassette range.

Design & Construction

The FC-RS520 uses a 4-arm crank construction in aluminium, delivering a balance of stiffness, durability, and weight that suits everyday training and sportive riding alike. The two-piece Hollowtech II design is straightforward to install and service, and is compatible with a wide range of threaded and press-fit bottom brackets (sold separately).

Compatibility & Fit

Compatible with Shimano 12-speed HG road drivetrains. Spindle interface: Shimano Hollowtech II (24mm). BCD: 110mm Asymmetric. Chainline: 44.5mm. Q-Factor: 150mm. Bottom bracket shell width: 68/70mm (threaded); compatible with equivalent press-fit widths via adapter. Designed for disc brake road frames with 135/142mm O.L.D. and chainstay length 415mm or greater. Bottom bracket not included. Pedal thread: 9/16".