Examples
Examples
Try the starting example
- Bottom-bracket shell width (mm)
- 68
- Front ring plane right of right shell face (mm)
- 15
- Rear hub locknut width (mm)
- 135
- Drive locknut to reference cog plane, inward (mm)
- 20
- Axial separation between sprocket planes (mm)
- 400
- Front ring plane right of bicycle centre (mm)
- 49
- Reference rear cog plane right of centre (mm)
- 47.5
- Front minus rear chainline (mm)
- 1.5
- Ideal lateral chain angle (degrees)
- 0.214858
Try another scenario
- Bottom-bracket shell width (mm)
- 68
- Front ring plane right of right shell face (mm)
- 13.5
- Rear hub locknut width (mm)
- 135
- Drive locknut to reference cog plane, inward (mm)
- 20
- Axial separation between sprocket planes (mm)
- 400
- Front ring plane right of bicycle centre (mm)
- 47.5
- Reference rear cog plane right of centre (mm)
- 47.5
- Front minus rear chainline (mm)
- 0
- Ideal lateral chain angle (degrees)
- 0
Calculation method
Calculation method
Front ring plane right of bicycle centre (mm)
Shell width/2+entered ring offset.
Reference rear cog plane right of centre (mm)
Rear locknut width/2−entered cog inset.
Front minus rear chainline (mm)
Front plane−rear plane; positive means front lies farther right.
Ideal lateral chain angle (degrees)
atan2(front−rear plane,axial separation), in degrees.
Symbols and units
- a
- Bottom-bracket shell width (mm)
- b
- Front ring plane right of right shell face (mm)
- c
- Rear hub locknut width (mm)
- d
- Drive locknut to reference cog plane, inward (mm)
- e
- Axial separation between sprocket planes (mm)
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
- A comparison to one specified rear cog plane. It does not choose the proper chainline, model the entire cassette or approve drivetrain compatibility.
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: chainline measurements ↗
Background reading; this does not imply endorsement or independent review of SumFizz.