. splined bottom bracket for use with Shimano Octalink chainsets. oversize BB spindle – Large 22 mm diameter hollow cold forged chrome-moly Pipe billet spindle reduces weight, increases strength and rigidity. octalink splined axle/crank arm interface – results in more rigid crank assembly compared to square tapered spindle. sealed cartridge assembly with oversize ball Bearings – maintenance-free high Efficiency Rubber seals keep out dirt, mud and water. cartridge design allows easy installation without adjustment.