Fsa slk mexo 386 xx1 crank armsthe crank arms are unidirectional carbon fibre with an alloy spine inside to boost strength with a minimal weight penalty it also features a forged 7075 mega exo spindle and is designed to work with fsa 386 chainrings that have 3 bolts on the spider features ud carbon composite arms with alloy spine includes both arms spindle finish ud carbon finish bcd 86mm bottom bracket mega exobuy fsa components from chain reaction cycles the worlds largest online bik