The shimano dura ace rd 9000 11 speed rear derailleur features a redesigned rear system with a new spring mechanism the shifting operation has also been improved to make it lighter shorter and more equal the derailleur has a wide link design to reduce shifting deflection and increase rigidity to allow for more precise shifting over an extended time period the dura ace range is the lightest most ergonomic and most precise groupset shimano have made and this rear derailleur features a carbon