Wheel Spoke Length Calculator
Calculate the correct spoke length for wheel building from hub flange dimensions, ERD, cross pattern, and spoke hole count.
Inputs
Results
Spoke Length (rounded to nearest 0.5mm)
294 mm
≈ 3 credit cards
How to Use This Calculator
- Enter the Hub Flange Diameter and Hub Center to Flange distance in millimeters.
- Set the Effective Rim Diameter (ERD) in millimeters from the rim manufacturer.
- Select your Cross Pattern (Radial through 4-cross) and Spoke Hole Count.
- Review the recommended Spoke Length rounded to the nearest 0.5mm.
- Order spokes using the exact length to minimize trim work during lacing.
How the result changes with Effective Rim Diameter (ERD)
| Effective Rim Diameter (ERD) | Spoke Length (rounded to nearest 0.5mm) |
|---|---|
| 515 | 250.5 mm |
| 553 | 269 mm |
| 598 | 291.5 mm |
| 635 | 309.5 mm |
What each input means
- Hub Flange Diameter
- The bolt circle diameter of the spoke holes on the hub flange. Measure center-to-center across two opposite holes.
- Hub Center to Flange
- Distance from the centerline of the hub to the center of the flange. Left and right may differ — use the side you are calculating for.
- Effective Rim Diameter (ERD)
- The diameter to the spoke nipple seat inside the rim. Found in rim manufacturer specs or measured directly.
- Cross Pattern
- The lacing pattern. 3-cross is standard for rear wheels. Radial is common for front non-disc wheels.
- Spoke Hole Count
- Total number of spoke holes in the hub (and rim). Must match between hub and rim.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersHub Flange Diameter = 58, Hub Center to Flange = 35, Effective Rim Diameter (ERD) = 604, Cross Pattern = 3 = 5 input(s) provided
- Calculate Spoke LengthSpoke Length294 = 294
- Calculate Exact Spoke LengthExact Spoke Length294.2 = 294.2
- Calculate Radial Spoke LengthRadial Spoke Length275.2 = 275.2
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