Shimano GRX 600 & 800 Groupset Components
Shimano GRX is aimed at gravel, adventure and bikepacking. It offers lower gears better suited to riding steep, rocky terrains or muddy paths and, in a first for Shimano, ready-made 1× gearing options (i.e. with a single chainring at the front).
GRX isn’t a groupset per se, it’s a range of components that complements Shimano’s existing groupsets, with components at Tiagra, 105, Ultegra and Ultegra Di2 levels. The naming scheme looks like this:
Tiagra level: RX400
105 level: RX600
Ultegra level: RX800 (Ultegra mechanical shifters are ST-RX810, Ultegra Di2 shifters are ST-RX815)