Coming from a road groupset and looking at your first gravel build, or replacing a worn 11-speed GRX crank and stepping up to 12-speed, the FC-RX610 is where most riders land when they want the double-chainring setup without paying for the RX820. Shimano's GRX FC-RX610 2x Crankset uses a 46/30T chainring combination on a Hollowtech II two-piece hollow aluminum arm, giving you the tight gear steps of a double alongside a genuinely low bailout gear when the road tilts up.

The 46/30 gearing is the number to pay attention to. Paired with an 11-34T or 11-36T cassette, you get close ratios across the middle of the cassette where you'll spend most of your time on rolling gravel, plus a 30-tooth inner ring that gets you climbing gears approaching what a 1x with a 10-51T cassette delivers. That's the tradeoff versus the FC-RX610-1: the 2x keeps cadence steady in a group and gives you road-speed top gears, where the 1x wins on simplicity and range spread.

Crank arm lengths cover 165mm, 170mm, 172.5mm, and 175mm. The 165mm option is the one to flag if you're running a smaller frame with wider tires and pedal strike is a concern, or if you've been experimenting with shorter cranks for hip clearance on long rides.... Read More