The shimano bb5500 105 bb 68to109 mm is a splined bottom bracket designed for use with shimano road octalink crankset the oversize bb spindle is a large 22 mm diameter chrome moly hollow pipe billet spindle reduces weight increases strength and rigidity the octalink splined axlecrank arm interface results in a more rigid crank assembly compared to square tapered spindle maintenance free sealed cartridge design prevents corrosion and is easy to install this bottom bracket has an aluminium a