The Shimano XTR FD-M9020-L Front Derailleur is a Side Swing-type front derailleur designed for use with Shimano's new XTR 2x drivetrains, and it includes Shimano's "L" adapter for Low Clamp mounting. What the heck does all that mean? Keep reading.
Shimano's new 9000-series XTR drivetrain has shaken up the mountain bike world, but not just with the industry-first Di2 electronic version. The mechanical version revolutionizes things in its own fashion, too, and most specifically in the front derailleur. The new alloy cage and titanium hardware are even stronger and lighter than before, sure, but that's not the big news. To better accommodate new suspension designs, as well as the rising popularity of two-chainring drivetrains, Shimano introduces its Side Swing derailleur design, which is routed from the front of the derailleur. The benefits include a lighter overall design, an additional 15mm of tire clearance, and pull strength that increases by up to 100% for reduced effort and faster shifting.
Cable routing changes, too, which means some frames can't accept the new design (for those, see the M9025 series of XTR front derailleurs), but those that can will see the front derailleur cable jump across the main triangle as the cable runs down the top tube. The best part of the Side Swing design is that there is only one M9020 derailleur — that D, E, H, or L only signifies the type of clamp adapter it comes with. To use the same derailleur on a different frame, just swap out the adapter type for whichever one the new frame requires. If your frame can accommodate a front derailleur cable running down the down tube, just figure out which type of FD mount you need (High Clamp, Low Clamp, High Direct, or E-Type), and pick from the four versions of the M9020 are available.