The new sram s900 offers an option between the sram rival oct and the sram force crankset the s900 utilizes a new unidirectional carbon crank arm with a forged alloy spider this crank arm is also used with srams srm and quarq power meter systems the sram s900 includes our proven power glide chainrings and uses gxp bb system it comes in full size and compact ratios and in multiple crank arm lengths