Shimano GRX Shadow Plus RD-RX820 12-speed Rear Derailleur

Shimano GRX RD-RX820 - reliable and quiet gravel rear derailleur for 2x12-speed

The Shimano GRX RD-RX820 12-speed rear derailleur is designed for gravel use with 2x drivetrains and a wide-range road bike cassette. It scores with quiet, reliable shifting and excellent chain security. RD-RX820 has a capacity of 42 teeth and is compatible with 34 and 36 teeth on the largest cassette sprocket. It features Shadow Plus technology, an integrated chain stabiliser, which prevents the chain from slapping on rough surfaces and thus counteracts chain drop. The function can also be switched off when you are riding on smoother roads or when you want to remove the wheel. The model is largely made of aluminium and therefore does not weigh a gram too much. The bearings of the guide and tension pulley wheels contribute to the smooth performance.

Specifications:

Series:

GRX RX820

Application:

Gravel

Gearing:

12-speed

Mount:

standard (Direct Mount compatible)

Capacity:

42-tooth

Compatibility:

Shimano Road 12-speed

Compatibility - Chains:

HG 12-speed

Technical Information:

Derailleur Pulleys:

13 tooth (bottom, tension pulley), 11 tooth (top, idler pulley)

Outer Cage Material:

aluminium

Inner Cage Material:

aluminium

Other Materials:

aluminium, composite material (GFRP), stainless steel, steel

Compatibility:

Shift/Brake Lever:

ST-RX820, ST-RX610, ST-R7120

Cassette:

CS-R8101-12 (11-34 only), CS-R7101-12, CS-HG710-12

Chain:

CN-M8100, CN-M9100, CN-M7100, CN-M6100

Features:

• mechanical rear derailleur for gravel bikes with 2x12-speed setup
• safe and quiet shifting on mixed surfaces
• smooth and reliable gear changes
• adjustable chain stabilisation prevents chain drop
• stabiliser with on/off switch to adapt to the terrain and for easy wheel removal
• flat design prevents getting stuck on obstacles
• painted cage plates
• derailleur pulley bearings
• 4 pivot bushings, fluorine-coated

Technology:

Shadow RD+
Shadow Plus rear derailleurs are just as low-profile as Shimano's Shadow rear derailleurs. In addition, a stabilizer with on/off switch is used to reduce chain slap and thus counteract chain drop. At the same time, this results in a quieter drive. Weight is also saved compared to other chain restraint devices.

OT-RS900
For Dura-Ace, Ultegra, 105, GRX and other 11-speed or 12-speed road and gravel rear derailleurs, Shimano has developed the special OT-RS900 cable housing. It is less stiff than the conventional OT-SP41 housing and is therefore better suited to the tight curve where the cable is routed from the frame to the rear derailleur. Thanks to OT-RS900, problems with the barrel adjuster can be prevented and the rear wheel can be removed more easily. OT-RS900 is not intended for use on the shift/brake lever side.

Models:

short:

Max. Largest Sprocket Teeth:

36-tooth

Min. Largest Sprocket Teeth:

34-tooth

Max. Smallest Sprocket Teeth:

11-tooth

Min. Smallest Sprocket Teeth:

11-tooth

Max. Chainring Difference:

17-tooth

Total Capacity:

42-tooth

Manufacturer Number:

IRDRX820

Contents:

• 1 x Shimano GRX RD-RX820 Shadow+ rear derailleur
• 1 x Shimano OT-RS900 240 mm cable housing
• 1 x long nose end cap