Examples
Examples
Try the starting example
- Usable post length along axis (mm)
- 400
- Exposed post length along same axis (mm)
- 200
- Post minimum insertion from its specification (mm)
- 100
- Frame minimum insertion from its specification (mm)
- 120
- Measured maximum unobstructed insertion (mm)
- 250
- Actual insertion (mm)
- 200
- Controlling entered minimum (mm)
- 120
- Margin above controlling minimum (mm)
- 80
- Remaining insertion before entered obstruction (mm)
- 50
- Comparison with entered dimensional limits
- Within entered dimensional limits
Try another scenario
- Usable post length along axis (mm)
- 400
- Exposed post length along same axis (mm)
- 300
- Post minimum insertion from its specification (mm)
- 100
- Frame minimum insertion from its specification (mm)
- 120
- Measured maximum unobstructed insertion (mm)
- 250
- Actual insertion (mm)
- 100
- Controlling entered minimum (mm)
- 120
- Margin above controlling minimum (mm)
- -20
- Remaining insertion before entered obstruction (mm)
- 150
- Comparison with entered dimensional limits
- Below entered minimum
Calculation method
Calculation method
Actual insertion (mm)
Usable post length−exposed length.
Controlling entered minimum (mm)
max(post minimum,frame minimum).
Margin above controlling minimum (mm)
Actual insertion−controlling minimum.
Remaining insertion before entered obstruction (mm)
Maximum unobstructed insertion−actual insertion.
Comparison with entered dimensional limits
Compare against both supplied limits without inferring material or clamp compatibility.
Symbols and units
- a
- Usable post length along axis (mm)
- b
- Exposed post length along same axis (mm)
- c
- Post minimum insertion from its specification (mm)
- d
- Frame minimum insertion from its specification (mm)
- e
- Measured maximum unobstructed insertion (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
- Checks dimensions you have read from the post/frame specifications and measured inside the frame. A dimensional result does not approve the seatpost, clamp or frame combination.
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
Park Tool: seatpost minimum-insertion markings ↗
Background reading; this does not imply endorsement or independent review of SumFizz.