Shimano GRX RD-RX817 Rear Derailleur (Di2, for 11-40/42)

The Shimano GRX RD-RX817 Rear Derailleur boasts a built-in chain stabilizer for seamless and accurate shifting on all terrains. Its ON/OFF switch allows for a quieter ride on smooth surfaces, while the Di2 version offers digital precision and synchronized shifting. This derailleur is also compatible with MTB cassettes up to 42T.

- Adjustable, gravel-tuned chain stabilizer prevents chain slapping and drops
- Switch stabilizer ON/OFF to match the terrain
- Silent and uninterrupted rear shifting on rough terrain
- Compatible with current road Dual Control Levers
- High cog: Max. 11T/Min. 11T
- Low cog: Max. 42T/Min. 40T
- Total capacity: 31T