Deore XT is a mountain and touring bike groupset first introduced by Shimano in 1983.
[1] It was Shimano's first mountain bike groupset, based on their existing Deore touring groupset, and it consisted of a triple-, double- or single chainring crankset, front and rear derailleurs, handlebar-mounted "finger" shifters, cantilever brakes, and large-flange hubs.
[1] Since then, it has become their "second-tier" offering, the list of components has expanded to include hydraulic disc brakes, a complete wheelset, a chain, and clipless pedals,[2] and it is offered in silver or black finish.
[3] The groupset was designated by model numbers M7xx; beginning with M700,[1] and ran to M780.
Current groupsets are designated by model numbers M8100 and T8000.