Based on the seat tube diameter, it wouldn't be Cromor. While Cromor is a double butted tubeset, it uses a single butted seat tube, with the butt at the bottom end. The wall thickness at the seat post end is 0.6mm. Consequently, it typically uses a 27.2mm seat post. A post diameter of 26.8mm would be typical of the plain gauge Aelle and Gara tubesets. 26.4mm is even smaller and down in the range of a lightweight hi-tensile steel. You should check the seat cinch slot for notable pinching at the top. Maybe the previous owner installed an under size seat post?
Last edited by T-Mar; 12-23-19 at 07:58 AM.