The Shimano FC-RS520 brings 12-speed performance to road cyclists seeking smooth, reliable shifting at an accessible price point. Designed for 2x12-speed drivetrains, this crankset pairs 50/34T chainrings with Shimano's trusted Hollowtech II spindle interface — giving you confident power transfer whether you're climbing switchbacks or pushing pace on the flat.

Highlights

• 2x12-Speed ready: Engineered for Shimano 12-speed road drivetrains, compatible with HG 12-speed chains.
• Hollowtech II interface: Industry-proven two-piece crank design delivers stiff, efficient power transfer and straightforward installation.
• 110 Asymmetric BCD: Dedicated 4-arm spider geometry optimised for the 50/34T double chainring configuration.
• 50/34T chainring combo: Versatile gearing range suited to everything from flat training rides to hilly gran fondos.
• Disc-brake optimised chainline: 44.5mm chainline and 150mm Q-factor matched to modern road disc geometry.
• Aluminium construction: Durable alloy crank arms offer reliable longevity at an accessible weight.

Construction & Design

The FC-RS520 uses Shimano's two-piece, four-arm crank architecture. The 24mm Hollowtech II spindle is integrated into the non-drive arm, threading through the bottom bracket shell for a secure, rattle-free fit. The 4-arm spider keeps chainring bolt positions consistent, and the 110 asymmetric BCD accommodates Shimano 12-speed double chainrings for precise front shifting.

Compatibility & Fit

The FC-RS520 is designed for 2x12-speed Shimano road drivetrains. Compatible with 68mm and 70mm threaded bottom bracket shells (bottom bracket sold separately — 24mm spindle required). The 44.5mm chainline suits frames built around 135mm or 142mm O.L.D. road disc hubs with a chainstay length of 410mm or greater. Compatible with HG 12-speed chains. This listing is for the 172.5mm crank arm length with 50/34T chainrings.