The SHIMANO DEORE XT FC-M8120-B2 crank features an entirely new construction using direct mount chainrings special gear tooth profile for improved chain retention and a 178mm Q-factor. Special MTB gear teeth profile improves chain engagement and retention Hollow forged crank maximizes power transfer while limiting weight Superior chain retention Rigid and lightweight design for aggressive trail riding Q-factor 178 mm Chainline 55 mm Weight 616 g 28T 630 g 30T 628 g 32T 642 g 34T 660 g 36T