The diameter of a suspension seatpost varies, but some sizes are more common than others.
While suspension seatposts are available in multiple diameters to fit different bike frames, there isn't a single "the" diameter. The most common sizes are:
- 27.2mm
- 30.9mm
- 31.6mm
Additionally, 34.9mm is becoming increasingly popular, especially on mountain bikes.
Therefore, to determine the correct diameter for your bike, you need to measure the internal diameter of your bike frame's seat tube, or check the specifications of your current seatpost.
