The idea behind the Spire Crank was to take the proven 2 & ½ piece system and combine it with a super tough, box-section arm design that will remain incredibly stiff and dent resistant. After a year of testing from Bruno Hoffmann and the rest of the PRO team, the end result is a super strong and reliable crank built to shred. Now available in a super-short 160mm version for use with shorter 12.5″-13″ chainstay frames. MaterialTubular heat-treated 4130 crmo arms & crmo axle Length160mm, 170mm or 175mm Axle22mm crmo ultra hollow ColorsBlack, satin oilslick, c.p. FeaturesStrong, lightweight crank / RSD & LSD compatible / 22mm hollow heat-treated spindle / smooth and rounded ankle friendly spindle boss Weight901g (31.78oz) 170mm