25.4mm Wide Seatpost in 27.2mm Frame


I have a Kris Holm 25.4mm wide seatpost. Will this seat post be able to fit snug enough in a 27.2mm Impact gravity frame? What I’m wondering is if a couple of mm will make a difference in tightness when the frame is just a few mm bigger. I am in a slight hurry so if you guys could respond and help me out that’d be great!


You would need a shim; just trying to tighten it won’t work. You can get them online, or get lucky at a local bike shop (but there are so many size possibilities that you probably won’t find the right one, and the “adjustable” ones don’t work in my experience).

You could also try making your own shim out of sheet aluminum or even something like a piece of hose, though it won’t be as secure as a proper one.

Adapter shims:
Here’s one on ebay.
Here’s one on amazon.

I have use a piece or two of plastic yoghurt or butter container for this type of thing.
Thin and very strong.
You would need to renew occasionally if you were moving the post often.

soda cans work even better! i am riding with a shimed post right now