Shimano Deore M590 Crank/Bottom Brackets SetsChainring spider is not removableAll 3 chainrings are steel and replaceable unless noted otherwise9 spd compatibleHyperdrive chainrings with aluminum outer ringItem SpecificationsColorBlackBB Thread TypeEnglishSpindle Interface TypeHollowtech IIPedal Spindle9/16"Bolt Pattern4-BoltChainring BCD64,104mmArm Length175mmRings22-32-44Crank-FD TypeMountain TripleBB Shell Width68mmCrank Intended UseMountainChain Compatibility9-Speed