Working alongside our World Cup DH and Enduro athletes, e*thirteen engineered the new Helix Race GR Cranks. These Forged AL-6066-T6, CNC-sculpted aluminum cranks are designed for the rigors of downhill, big bike park laps, enduro, and freeride. The Helix Race GR shares the spindle design and low-profile shape with our top-end carbon and alloy cranks, with 83mm and 73mm spindle options. Helix Race GR cranks easily exceed ASTM 5 standard -- a work of art made to take a beating. - Exceeds ASTM 5 standards for Downhill, Bike Park, Enduro and Freeride applications - Forged, CNC Machined, AL-6066-T6 arms and 30mm AL 7050-T7 spindle - 73mm and 83mm spindle options for enduro and DH bikes - Available in popular gravity crank arm lengths, 160mm and 165mm - Molded crank boots, protective polymer decals, APS adjuster, and self-extractor system included - 83mm crank requires the Helix GR Chainring. 73mm crank requires a standard Helix chainring.