Shimano GRX RD-RX820 Rear Derailleur

The Shimano GRX RD-RX820 Rear Derailleur is designed for 12-speed gravel and mixed-terrain riding, delivering reliable shifting performance and enhanced drivetrain stability across a wide range of conditions. Built for Shimano GRX 12-speed systems, it supports 1x setups with 11–34T and 11–36T cassettes, providing versatile gearing for steep climbs, fast descents, and long-distance gravel riding.

The derailleur features Shimano’s Shadow RD+ clutch system, which increases chain tension to reduce chain slap and improve chain retention on rough surfaces. The ON/OFF switch allows riders to disengage the clutch when needed, making wheel removal and drivetrain maintenance easier.

Optimized for use with Shimano HG 12-speed chains, the RD-RX820 is engineered for durability, stable shifting, and consistent performance in demanding gravel environments.

Key Features

• GRX 12-Speed Gravel Design – Built for reliable performance across mixed terrain and long-distance riding
• 11–34T / 11–36T Cassette Compatibility – Wide gearing range for climbing and high-speed gravel riding
• Shadow RD+ Clutch System – Improves chain stability and reduces chain slap on rough terrain
• ON/OFF Stabilizer Switch – Enables clutch control for easier wheel changes and maintenance