The shimano 105 5500 bottom bracket comes with an octalink splined axlecrankarm interface in either 109mm or 118mm lengths and is designed for use with the shimano road octalink crankset the oversize bb spindle has a large 22mm diameter chrome moly hollow pipe billet spindle to reduce weight and increase strength and rigidity and the octalink splined axlecrank arm results in a more rigid crank assembly compared to a square tapered spindle the maintenance free sealed cartridge design preve