When Direct Mount first arrived on the market, we shuttered to think of yet another front derailleur design in an already overcrowded area of componentry. That feeling didn't last long after we realized how much sense they made. With more complex suspension designs, it has become increasingly harder to shoehorn in a front derailleur with all of the entanglements of links, pivots and swing arms. The Direct Mount addresses some of these issues. With D-Mount, it is now possible to mount the derailleur directly to the outside of the frame instead of attempting to mount it around the downtube. The clamp is black anodized and matches the rest of the 780 series components while the cage is coated for added durability and chain glide. Set screws are located on the outside of the derailleur for easy adjustment.
The Shimano XT M781 and M786 are designed to work with Shimano's 10 speed mountain groups. The M786 is for use with 2x10 while the M7851 is for a 3x10 set up. The difference being in the cage profile. A 2x10 crank requires a smaller diameter cage with a different throw and conversely, a triple crank requires just the opposite.