Gravel bikers, bikepackers and crossers are the target group for Shimano's new GRX groupset. It offers an extreme variety of options: mechanical or electronic shifting as well as 11-speed or 10-speed variants with one or two chainrings. The RX800, RX600 and RX400 versions offer components for 1x11-speed, 2x11-speed and 2x10-speed respectively. A special feature are the optional additional brake levers, which can also be used to operate the hydraulic disc brakes from the top handlebar position. If you are riding with just one chainring, you can also use the mechanical left shift lever to control a dropper post instead of the front derailleur.
The front derailleur leaves room for tyres up to 42 millimetres wide and is therefore only compatible with the matching GRX cranks, which have a modified chainline. However, rear derailleurs and front derailleurs from the GRX range can also be controlled with the current road bike levers (mechanical or Di2).
The GRX groupsets are combined with chains and cassettes from Shimano's existing MTB or road groupsets. The wide range of variants requires a precise selection of suitable components; there are a total of five different rear derailleurs in the GRX series. If you use an 11-30 to 11-34 cassette from the Ultegra, 105 or Tiagra groupsets, you will need the RD-RX815 (Di2) or RD-RX810 (mechanical) rear derailleur. If you are using an 11-40 or 11-42 MTB cassette from the Deore XT, SLX or Deore groupsets, you will need the RD-RX817 (Di2) or RD-RX812 (mechanical) rear derailleur with a longer cage. Finally, there is an RD-RX400 for the 10-speed setup.
Two new wheelsets are also part of the group. The WH-RX570 is designed for the 700c tyre size and is said to weigh 1600 grams, while the WH-RX570 is designed for the 650b size and weighs 1540 grams according to the manufacturer. Both versions can be ridden with tubeless tyres.
The mechanical groupsets will be available from June and the electronic components from August 2019. Shimano has not specified purchase prices.
