Shimano m5100 deore 11 speed double chainsetengineered for maximum performance on every mtb adventure, this double crankset delivers fast acceleration and smooth shifting operation on the toughest of rides. It features a forged alloy crank arm construction, which makes it perfect at handling all the abuse that's associated with all day epics in the mountains. Shimano has also equipped it with a hollowtech ii integrated bottom bracket for increased stiffness, efficiency and added durability.features crank arm material forged alloy use mtb speed 11 speed number of chainrings 2 chainrings included yes crank arm length multiple options available chainline 48.8mm chainring bcd for use with 135 142mm o.l.d. Frames chainring tooth count 36 26t 5 arm or 4 arm 4 arm design 2 piece compatibility 11 speed mtb drivetrains is bb included hollowtech ii integrated bottom bracketpart numbers 175mm fcm5100e66 170mm fcm5100c66technologies hollowtech ii hollowtech ii integrated bottom bracket design uses a wide bearing placement with a large axle diameter for increased stiffness, efficiency and added durability. Sg x chainring sg x chainring with patented spike pins give smooth and fast gear shifts under load. A 2 year warranty is offered with all shimano products from chain reaction cycles 3 years on dura ace and xtr products.buy shimano components from chain reaction cycles, the world's largest online bike store.