Duragrouch Yes, I can't find a "plain" cylindrical vertical post either. Tho, the diameter of my folding stem just below the bar clamp measures 28.5mm which will pretty much fit any normal mtb stem (28.6) with a bit of shimming or sanding. So, if the measurements are right, a somewhat extreme method would be to cut the top bar clamp off, install a star-spangled nut into the post and use any mtb stem. But with this method, the post height will be about 3-4cm shorter than before accounting for the loss of the bar clamp..