Fsa sl k carbon mexo 386 xx1 cranksetthe advent of super wide range 11 speed cassettes on mountain bikes has made a single chainring setup a real option for many riders the sl k compact single uses fsas 386 three armed spider that delivers huge stiffness the crank arms are unidirectional carbon fibre with an alloy spine inside to boost strength with a minimal weight penalty the chainring is cnc machined from high strength 7075 aluminium the rings are optimised for use with 11spd transmissi