A key component of the new Shimano GRX 12-speed groupset, this rear derailleur is packed with features. Equipped with an integrated chain stabiliser, the Shimano GRX RD-RX820 helps prevent chain rattling and skipping for safer handling on rough terrain. Gear changes are smooth and quiet.

The chain tensioner features an ON/OFF switch, as found on the MTB range, to improve chain retention on all terrains. Compatible with 12-speed cassettes in 11-34T and 11-36T, this Shimano GRX RD-RX820 rear derailleur offers a wide gear range so you can maintain the best cadence on every ride.

Technical specifications:

- Part number: RD-RX820
- Weight: 270 grams
- 12-speed
- Maximum chainring difference: 17T
- Small sprocket: Max. 11T / Min. 11T
- Large sprocket: Max. 36T / Min. 34T
- Total capacity: 42T
- Shimano Shadow RD+ technology
- ON/OFF switch
- Chain stabiliser