The deore fc m590 crankset has an attractive looking finish firm 2 piece construction with outboard bearing system the integrated hollowtech ii axle offers increased stiffness at low weight with shimano hyperdrive sg x sprockets dual sis compatible shimano deore fc m590 175mm 48t specifications material aluminium small sprocket steel colour silver arms black ring bolt circle 104 64mm comes complete with bottom bracket for 68 and 73 mm frames chainring sizes 483626t crank