Shimano GRX RD-RX817 Di2 11-Speed Shadow+ Rear Derailleur

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.

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. It isn’t a reworked set of road components. It represents a ground up look at how cyclists want to explore their world. Shimano GRX helps you eliminate excuses, instead urging you to try that rough sidetrack or ride that little bit longer. It offers you the option to Explore Beyond.

Technology

SEIS

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.

This electronic shifting system has been extensively tested over past two years by several professional riders in all conditions possible, such as rain, mud, low temperatures, cobble stone roads and combinations of all of these at the same time.

Shifting is executed by simply pressing the button. No power is needed to shift, which gives important advantages since it is easier now to always keep a tight grip on the handlebar and to keep your concentration on riding instead on shifting.

The shift system allows accurate and effortless shifting in difficult circumstances for example when you have cold hands or when you are completely exhausted. Furthermore, the shifting performance will never be affected by contaminated or stretched cables since the shifting signal is transferred electronically. The operating buttons work similarly to mechanical Dual Control Lever so you don’t need to re-program your mind for the SEIS.

E-Tube

E-Tube is Shimano's “service” that uses websites or apps to maximize the enjoyment of riding a bicycle by connecting the riders, the bicycles and Shimano.

Shimano’s genuine application E-Tube Project for Mobile allows you to customize your bike, update firmware, and maintain it by connecting it wirelessly to your bike. You can also get the more detailed bike maintenance by connecting to your bike by wire with E-Tube Project for Windows V4 application.

• Easily update to the latest firmware with the user-friendly interface
• Set two e-bike assist profiles to your preference, and customize the assist characteristics according to the riding situation
• Design your favorite Di2 gearshift in Synchronized Shift
• Easily adjust both front and rear derailleurs via application

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

Features

• Low profile Shadow Plus design 11-speed rear derailleur with Di2 technology for fast and precise shifting performance
• Shadow Plus uses a chain stabilising switch that when on will reduce chain bounce in rough terrain maintaining more stable drive and shifting
• High tolerance cold forged aluminium link plates and body construction is extremely light and durable
• 11-speed E-tube Di2 compatible
• Compatible with 11-speed HG chains
• Wide gear ratio compatible up to 11-42 Tooth
• For use with single chainset