Examples
Examples
Try the starting example
- Effective rim diameter at nipple seats (mm)
- 600
- Hub flange spoke-circle diameter (mm)
- 60
- Flange-to-rim-centre axial distance (mm)
- 40
- Spokes on this flange
- 18
- Crossings for this flange
- 0
- Ideal spoke centreline length (mm)
- 272.946881
- Spoke projection in wheel plane (mm)
- 270
- Angular hole displacement (degrees)
- 0
- Ideal bracing angle (degrees)
- 8.426969
Try another scenario
- Effective rim diameter at nipple seats (mm)
- 600
- Hub flange spoke-circle diameter (mm)
- 60
- Flange-to-rim-centre axial distance (mm)
- 40
- Spokes on this flange
- 18
- Crossings for this flange
- 3
- Ideal spoke centreline length (mm)
- 288.963666
- Spoke projection in wheel plane (mm)
- 286.18176
- Angular hole displacement (degrees)
- 60
- Ideal bracing angle (degrees)
- 7.956759
Calculation method
Calculation method
Ideal spoke centreline length (mm)
sqrt(rimRadius²+flangeRadius²+axialOffset²−2×rimRadius×flangeRadius×cosθ).
Spoke projection in wheel plane (mm)
sqrt((rimRadius−flangeRadius×cosθ)²+(flangeRadius×sinθ)²).
Angular hole displacement (degrees)
θ=360×crossings/spokes-on-flange.
Ideal bracing angle (degrees)
atan2(axial offset,in-plane projection), converted to degrees.
Symbols and units
- a
- Effective rim diameter at nipple seats (mm)
- b
- Hub flange spoke-circle diameter (mm)
- c
- Flange-to-rim-centre axial distance (mm)
- d
- Spokes on this flange
- e
- Crossings for this flange
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- An ideal centreline model from supplied ERD and flange measurements. It omits nipple engagement, spoke-seat corrections, hub-specific lacing and manufacturer rounding; it is not a purchase-length approval.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
Sheldon Brown: measurements for spoke-length calculation ↗
Background reading; this does not imply endorsement or independent review of SumFizz.