The Shimano GRX RD-RX822-SGS is the long-cage 12-speed rear derailleur at the heart of Shimano's GRX mechanical gravel groupset. Built for riders who want maximum range on remote dirt roads and challenging terrain, it accommodates 10-51T cassettes — delivering a wide spread of gears for everything from gravel sprints to loaded touring climbs. The integrated SHADOW RD+ clutch mechanism keeps the chain planted and quiet when the road gets rough.

Highlights

• Wide range 1×12 capability: Long-cage (SGS) design supports 10-51T cassettes with a 41T total capacity, giving you the full range of a 12-speed gravel drivetrain.
• SHADOW RD+ clutch: Shimano's proven SHADOW RD+ mechanism adds adjustable chain stabilisation, dramatically reducing chain slap, bounce, and drop on rough gravel and dirt roads.
• ON/OFF stabiliser switch: Quickly disengage the clutch tension for easy rear wheel removal and reinstall — no tools needed, no lost chain tension afterwards.
• Low-profile SHADOW design: The derailleur body sits close to the bike, reducing snag risk when navigating tight singletrack or loading the bike for travel.
• Optimised for gravel geometry: Engineered specifically for GRX gravel groupsets, with tuned cable pull and pivot geometry that complements Shimano's GRX shifters.
• Compatible with 12-speed HG chain: Works with Shimano's CN-M8100 and other 12-speed HG chains for precise, consistent shifting across the cassette.

GRX SHADOW RD+ Technology

The SHADOW RD+ clutch is central to what makes this derailleur a gravel-specific component. Standard derailleurs allow the cage to swing freely, which means vibration from rough terrain translates directly into chain movement — causing noise, dropped chains, and inconsistent shifting. The SHADOW RD+ mechanism adds rotational friction to the cage pivot, keeping the chain under constant tension regardless of the surface. When you're ready to remove the rear wheel, a simple lever disengages the clutch entirely. Re-engage it and you're back to full chain stabilisation without any adjustment.

Long Cage for Maximum Gear Range

The SGS (long cage) version of the RD-RX822 extends the pulley cage to accommodate the full 41T total capacity required by wide-range 12-speed cassettes. With a maximum low sprocket of 51T, this derailleur pairs with cassettes like the Shimano CS-M8100-12 or CS-M7100-12, opening up extraordinarily low gearing for steep climbs with loaded bags or in extended off-road terrain. The medium-cage GS variant (max 45T) is better suited to more moderate terrain; the SGS is for riders who want the biggest possible gear spread.

Compatibility & Fit

The RD-RX822-SGS is a 12-speed rear derailleur designed for 1×12 Shimano GRX drivetrains. It is compatible with 10-51T, 12-speed Shimano MTB cassettes (e.g. CS-M8100-12, CS-M7100-12) requiring a Micro Spline freehub. Total capacity is 41T. It uses a short-pull cable ratio and is intended for use with Shimano GRX 12-speed brake/shift levers (ST-RX820, ST-RX825). Compatible chain is 12-speed Shimano HG (e.g. CN-M8100). Mounts to a standard B-screw derailleur hanger. Colour: black.