You measure a seatpost binder bolt by determining the distance between the inner edges of the bolt's flanges when it is fully tightened but not installed in the frame. This is different from measuring the outer edges while the bolt is installed.
Here's a more detailed explanation:
- Key Measurement Point: Focus on the distance between the inner edges (faces) of the flanges.
- Condition: The bolt must be fully tightened.
- Installation State: The bolt should not be installed in the frame during measurement.
- Why This Matters: Measuring while installed, or measuring the outer edges, can give you an inaccurate reading due to frame tolerances or other factors.
| Measurement Parameter | Description |
|---|---|
| Point of Measurement | Inner edges of the flanges (faces) |
| Bolt Tightness | Fully tightened |
| Installation in Frame | Not installed during measurement |
| Goal | To determine the correct size needed for proper clamping force and fit. |
Essentially, you're measuring the gap that the bolt needs to close when tightened. This measurement determines the proper clamping force on the seatpost.
