I'm thinking about getting one of those adjustable-height seatposts for my Cinco, but they don't come in a 28.6mm size. Most are in a 30.9 or a 31.6 diameter, although Kind Shock is coming out with a 27.2 with a remote reservoir, so I could shim it up to the 28.6 if necessary.
Inside the seat tube of the Cinco, there is what appears to be an aluminum sleeve/shim that obviously reduces the diameter (but maybe also adds some sort of structural integrity to the frame). SO, the question I have for Jon (or perhaps someone else with this experience), is the sleeve/shim that is built into the frame removable? If so, can the frame be run without it? If so, what is that diameter?