New 1x12 drivetrain for gravel bikes: Shimano presents wireless GRX Di2 gravel rear derailleur

With the GRX RX827 Di2, Shimano presents its first completely wireless shifting system for gravel bikes. The new 1x12 groupset adds a wireless electronic option to the existing GRX range. A version with two chainrings and front derailleur is not offered in parallel.

According to Shimano, the system combines technologies from the company's road and mountain bike groupsets. The centrepiece is the new RD-RX827 rear derailleur, which is based on the XTR M9200 mountain bike rear derailleur. It has a compact design with a battery integrated into the rear derailleur, which can also be removed for charging. According to Shimano, one battery charge lasts for 700 to 1000 kilometres, depending on the riding conditions. In the event of impacts or falls, the rear derailleur should automatically return to its original position. The power supply for the shift lever is provided by the familiar button cells.

Extended compatibility and ergonomics

The groupset is compatible with all 12-speed Di2 components from Shimano, including the shifters for racing handlebars. This means that riders can also use the wireless shift levers of the Dura-Ace, Ultegra or 105 Di2 road bike groupsets; the unassigned left shift buttons can then be individually assigned to other functions, such as operating the bike computer. The flatbar shifters of the XTR and Deore XT Di2 mountain bike groupsets are also compatible. Within the GRX series, the BL-RX825-L brake lever without shifting function is now also available for the 1x12 drivetrain. According to Shimano, the ergonomics of the levers have been optimised for gravel bikes. They have a non-slip surface and are designed for handlebars with a flare curve.

Versatile application possibilities

With the new Shimano GRX RX827 Di2 groupset, Shimano is addressing different areas of application in the gravel segment. The robust design and wide gear range are suitable for both racing and bikepacking adventures. Thanks to its compatibility with mountain bike cranks, the system can also be mounted on dropbar mountain bikes. The chainring options available are 40 and 42 teeth. In combination with the 10-51 tooth cassette, this results in a range of 510 per cent. According to the manufacturer, the rear derailleur weighs 449 grams. Shimano states that the components can be retrofitted to existing gravel bikes without any special frame requirements. This means that riders can upgrade their existing bikes with the new technology.

Extended impeller range

In addition to the new groupset, Shimano is also presenting a new aluminium wheelset for gravel bikes. The WH-RX180-TL wheels are tubeless-compatible and have a rim width of 25 millimetres. They are suitable for tyres between 32 and 50 millimetres wide. The hubs can be converted between MICRO SPLINE and HG freehub bodies. This makes the wheels compatible with 10-, 11- and 12-speed cassettes. According to Shimano, the set weighs 2105 grams with an HG freehub and 2113 grams with a MICRO SPLINE freehub