- Step # 1 – Cut out a small strip of paper, say 1″ wide by 12″ long
- Step # 2 – Wrap this paper strip around the seat post;
- Step # 3 – Mark the both sides of the paper strip with a pencil;
- Step # 4 – Unfurl the strip and measure the distance between 2 marks;
- Step # 5 – Use this equation:
- Diameter (D) = Circumference (C) / Pi
For example, our circumference measured 3.4 inches, we would calculate the diameter this way:
D = 3.4″ / Pi
= 3.4″ / 3.14
= ~1″
So our diameter would round up to 1″.