Shimano ES51 Octalink V2 Bottom BracketReliable and timelessWe all need a new bottom bracket from time to time and if you're in search of an octalink 68mm bottom bracket then look no further. The Shimano ES51 bottom bracket utilizes Octalink technology which takes the conventional square taper design up a notch by improving the overall crankset and bottom bracket strength while also increasing the rigidity. A variety of different lengths allows you to pair the right bottom bracket with your bike. The ES51 is perfect for anything from the timeless Dura-Ace 7710 track crankset to the Sora 3500 series crankset. FeaturesOctalink tech improves on the rigidity and strength of the square taper designA variety of lengths to accommodate any crankset and bike68mm bb for standard threaded bottom bracket shells | Shimano | ES51 Octalink V2 Bottom Bracket 68 X 118mm