Shimano GRX DI2 RD-RX817 Rear Derailleurs

Suits 42T MAX MED CAGE SHADOW+

With an integrated chain stabilizer mechanism, the SHIMANO GRX derailleur provides a quieter experience and shifting security and precision on mixed terrain. For rides on smooth surfaces, the derailleur features and ON/OFF switch for the chain tensioner. The RD-RX817 DI2 version offers the digital precision of SHIMANO electronic shifting and synchronized shifting. and is compatible with mtb cassettes with a 42T low sprocket max.

Di2 - The revolutionary DI2 shifting system solves the challenges drivetrains present to the power-delivery equation in cycling. DI2 gives you instant, accurate, lighting-fast shifts the first and every time, at the push of a button. Even in the most extreme conditions, shifting is precise and controlled. You can change gear even under heavy load while climbing or accelerating. With DI2, you are in complete control.

E-Tube - The E-Tube platform's “Plug & play” and D-FLY wireless connections make it easier than ever to check the system's status, and apply customized settings to DI2 and Shimano Steps components with a PC, tablet or smart phone.

Shimano Electronic Intelligent System - A technological innovation of the computerized shifting system based on the DI2 concept with which is called, the SEIS (Shimano Electronic Intelligent System).
The SEIS innovative shift technology is still based on the Shimano Index System (SIS) that has proved its superior gear changing characteristics over the years. The big difference is that in this case, the shifting action is provided for by electronics instead of mechanics.

Shimano Shadow Rd+ - Less distraction quiet drive train. Rear derailleur stabilizer reduces chain slap. Simple solution for chain drop. Lighter and more efficient than roller type chain device.