Shimano FC-RX820 GRX chainset 48 / 31, double, 12-speed, Hollowtech II, 172.5 mm
FC-RX820-2 48x31t 172,5 mm. Shimano GRX, with its gravel specific ergonomics, optimized gearing options, rugged reliability, and quiet and stable drivetrain, sets itself apart from the rest of the component world.