Shimano RD-M986 XTR Shadow Plus 10 Speed Rear Derailleur
Shimano's M986 XTR Shadow Plus rear derailleur is a game changer. The innovative motion damping switch allows you to virtually lock out the bottom pulley of the derailleur, eliminating chain throw, chain slap, and extraneous drivetrain noise -- in other words the drivetrain issues you have while riding rough trails at high speed. Simply flip the switch to its -Inchoff-Inch setting to remove the wheel or fine tune the shifting. Combine that with the unobtrusive Shadow derailleur profile, improved cable pull ratio and sealed top and bottom pulleys and you get the paragon of all-mountain derailleurs.