Seat post sizes

Hey, I was wondering if a 27.2mm seat post would be stronger than a 22.2? That’s a stupid question but I’ve had both and they break rather quickly. Just wondering.


It depends more on the design of the seatpost than the size of the seatpost.

With everything else being equal a 27.2mm seatpost will be stronger than a 22.2mm seatpost but things are hardly ever always equal. It is possible to build a 22.2mm seatpost that is stronger than the 27.2mm seatposts you’ve broken. It’s not the size that matters. The design and construction of the seatpost is the more important part.

The advantage to the 27.2mm size is that you can get a very high quality bicycle seatpost, like the Thomson, in that size. You cannot get a Thomson seatpost in the 22.2mm size.

The larger diameter also means more surface area for the seatpost clamp. That means that a larger seatpost can theoretically be more secure from twisting ans slipping.

You can, however, get one in the 25.4mm size, which is the GB4 frame seat tube size, as well as many others.