Calculate precise spoke lengths for your next wheel build. Enter hub flange dimensions and rim ERD, or choose from common hub presets to get drive-side and non-drive-side lengths instantly.
Getting the right spoke length is the foundation of a well-built wheel. Spokes that are too long risk protruding through the nipple and puncturing the rim tape or inner tube, while spokes that are too short won't have enough thread engagement in the nipple, leading to a weak and unreliable wheel.
Professional wheel builders aim for spoke lengths accurate to within ±1 mm. Our calculator uses the standard geometric spoke length formula that accounts for hub flange radius, center-to-flange distance, rim ERD, spoke count, and cross pattern — the same method used by experienced mechanics worldwide.
The diameter of the bolt circle of spoke holes on the hub flange. Measure center-to-center across opposite spoke holes using calipers. Larger flanges generally result in stiffer, shorter-spoked wheels.
The distance from the hub centerline (midpoint between locknuts) to the center of each flange. On rear hubs this is asymmetric — the drive side is closer to center due to the cassette body.
The diameter of the circle where the spoke ends sit inside the rim. This is not the same as rim size (e.g., 700c). Check your rim manufacturer's specs or measure it directly using two opposing spokes and nipples.
How many times each spoke crosses other spokes from hub to rim. 3-cross is the most common for road and MTB wheels, providing excellent durability and power transfer. Radial lacing is sometimes used on front non-disc wheels.
Optimal tire pressure for your weight and tire size
Dial in your saddle height for comfort and power
Find the right frame size for road, MTB, and hybrid bikes
Determine optimal crank arm length for your build
Match handlebar width to your shoulder measurements
Calculate wheel diameter and convert tire size formats
Calculate precise spoke lengths for left and right sides of your wheel
Effective Rim Diameter — check your rim manufacturer specs
Enter your hub and rim measurements or select a hub preset to get started
Flange Diameter: Measure across the spoke hole circle on the hub flange, from hole center to opposite hole center.
Center-to-Flange: Measure from the hub centerline (midpoint between locknuts) to the middle of each flange. Use calipers for best accuracy.
Rim ERD: Insert two old spokes from opposite holes, seat fully, and measure tip-to-tip. Add both spoke lengths to that gap. Or check the rim manufacturer's documentation.