e*thirteen Helix Core Crankset - 170mm 73mm 24mm Spindle e*thirteen P3 Connect Interface BLKe*thirteen Helix Crankset 170mm 73mm 24mm Spindle with e*thirteen P3 Connect Interface Black. The e*thirteen Helix crank combines the 6066 T6 aluminum alloy arms with a smaller 24mm heat treated chromoly spindle to do so. Weight reduction features are designed into the mold to stay true to the strength and weight optimization with less CNC time and cost. Lighter weight for improved acceleration and climbing Strong enough to shuttle run bike parks