Shimano xt disc hub front 15mm m758performance xt hubs for use with disc or rim brakes features double contact seals with internal grease sleeve to keep the elements out and the grease in extending service life and maintain smooth operations even in the toughest terrain the hub uses angular contact bearings designed to cradle the balls giving both radial and lateral support for superior strength and durability in real world riding conditions they also offer precision bearing adjustment and ea