SIZES: 5.0 - 7.62 Axle for boards under 7.9 5.2 - 8.0 Axle for boards 7.9 - 8.1 5.6 - 8.25 Axle for boards 8.1 - 8.3 5.8 - 8.5 Axle for boards 8.3 - 8.6 6.1 - 8.75 Axle for boards 8.62 and Up