Spankyfart
Marin Fan
Thanks, I might look for one for my Syncros post. it's 26.8 (from a Zaskar LE)
The shims are for USE posts, which mostly are 25mm diameter., some are 27mm diameter also, you buy a shim for the USE post so you can use it in frames that do not have a 25mm seat tube.
In fact, there is a U.S.E. shim I can use, so I've ordered it. They have a thermo-plastic shim for a 27.2 seatpost in a 32.0 frame, which is exactly the same size difference (4.8mm) as 26.8 post in 31.6 frame. I might just have to widen the slot in the shim, depending on how narrow it is to start with, to allow it to fit in the 0.4mm smaller diameter seat tube.