Shimano Deore RD-M786-SGS as long cage version for Dyna-Sys 10-speed drivetrain. It features a switch which enables heavier spring tension to reduce chain bounce.
Chain bouncing can often cause noise as the chain slaps the top and bottom of the chain stay, or even derail from the front chain ring in extreme circumstances. The switch when set to the ON-position dampens the cage and therefore a consequent chain movement for a nearly silent and stable riding experience. In the OFF-position it eases the installation and removal of the rear wheel by relaxing the spring tension of the cage. The RD-M786-SGS Shadow Plus rear derailleur is only compatible with 10-speed Dyna-Sys shifting components.