Shimano front derailleurs are second to none, and the XT M770 Dyna-Sys front derailleur is no exception. Made of forged aluminum with a steel cage, the Bottom Swing derailleur can handle both top and bottom pull cable routing and also has spacers to accommodate all frame sizes. Between the top and bottom swing derailleurs, all frame designs are accounted for, unlike some other manufacturers derailleurs.
Weaknesses: Needs adjusted perfectly to prevent rub on all gears from middle ring.
Good front derailleur. Downshifts beautifully even under load which is great. Upshifts aren't quite as smooth. Because it is so narrow as a 10 speed setup you have to have it set up perfectly to prevent rub on all gears when in the middle ring. Overall not bad though!