So a question to the knowledgeable hubbers . Broke the Carbon seatpost on my Niner gravel bike 2 days ago . Not able to buy another post at the moment I decided to try a hack with a spare 25.4 carbon post I have . The first shim I made had a lip on it so it sat on the collar but wouldn’t tightened up enough to stop the seatpost turning around . Obviously because I had to make up the 1.8mm which is my big concern here . So I made another shim from the same tin and glued it inside the shim with the lip. So now it fits nice and tight and seems as if it won’t budge at all. My question is this : is trying to take up the 1.8 mm with a double shim dodgy ? Am not worried about the frame as it’s steel but am about the seatpost braking mid ride . The shim does goes past where the seat stays and top tube meet probably by about 3/4cm’s . The seatpost is also inserted about 20cm’s inside the seatpost tube. The collar now sits slightly higher than the collar as can be seen in the pics . Is 1.8 mm to much to take up with a shim? With it being a gravel bike the jarring the seatpost will take is it to much ? Is 25.4 to small for a gravel seatpost ? Keen to here everyone’s thoughts .
