my 80's peugeot is made with columbus slx tubing throughout and it takes a 26.8 seat tube.though 27.2 is more often than not the seatpost size for a lot of columbus tubesets .apparently there are exceptions. maybe because the frame is 61 c-t and intended for a larger heavier rider? maybe the french just like to be different? i,m no expert either.anyways.. kevin"heres my two cents worth" ruberg howell nj usa ps. vive le difference! or is it la?