HF-3 cranks are Promaxs top-of-the-line aluminum crank offering. Hollow-forged from 6061-T6 aluminum, both crank arms are hollow so they are super stiff, yet lightweight. The crank arms spin on a beefy 30mm spindle permanently fitted into the drive-side arm. These cranks offer direct-mount sprocket compatibility for additional weight savings, or run them with the included 104 BCD spider adapter.