The Shimano GRX FC-RX610-2 is a purpose-built 2x12-speed gravel crankset delivering the versatility and reliability demanded by mixed-terrain riding. With a wide-range 46/30T chainring combination and lightweight hollow-forged aluminium arms, it gives you the gear range to tackle everything from sealed climbs to rough gravel descents — all with the precise shifting performance GRX is known for.

Highlights

• Wide 46/30T gearing: A generous 16-tooth spread gives you tight steps on the flat and low gears for steep gravel climbs, keeping you riding efficiently across all terrain.
• Hollowtech II spindle interface: The proven two-piece design integrates the axle into the crank arm for a stiff, lightweight drivetrain connection that installs easily with standard tools.
• Hollow-forged aluminium arms: Material removed where it's not needed, leaving a crank arm that's stiff under load and light on the scale.
• 110/80 BCD chainring bolt pattern: Asymmetric bolt circle supports GRX-specific chainring geometry for optimised chain retention and shift quality across rough terrain.
• 12-speed GRX shifting: Engineered to pair with Shimano GRX 12-speed rear derailleurs and cassettes for consistent, reliable front shifting even under load on unpredictable surfaces.

GRX 12-Speed Drivetrain

The FC-RX610-2 sits within Shimano's 12-speed GRX groupset — a gravel-specific drivetrain built for real-world use. Compared to the RX810 tier above it, the RX610 delivers the same core GRX performance in a more accessible package without sacrificing the features that matter most to gravel riders. It's designed to work in harmony with GRX 12-speed derailleurs, cassettes, and shifters for a complete drivetrain system.

Design & Construction

The crank arms are hollow-forged from aluminium, with the 24mm steel axle integrated into the right-hand arm via Shimano's Hollowtech II system. A separate left-hand crank arm clamps on at the spindle end. The asymmetric 110/80mm bolt circle diameter accommodates the large outer ring and compact inner ring in a single, lightweight spider. Q-factor is 151mm and chainline is 47mm — dimensions chosen specifically for gravel geometry and tyre clearance.

Compatibility & Fit

Designed for Shimano GRX 12-speed groupsets. Compatible with 68mm or 70mm threaded bottom bracket shells (English/Italian). Requires a Shimano Hollowtech II-compatible bottom bracket — the SM-BBR60 or equivalent threaded unit is the standard pairing (sold separately). Crank arm length: 170mm. Chainring sizes: 46T outer / 30T inner. BCD: 110mm / 80mm. Chainline: 47mm. Q-factor: 151mm. Not compatible with 10-speed or 11-speed GRX drivetrains.