hhsrb

No, the barrel of the steerer clamp has some rigidity so the part above the top screw (and below the bottom screw) is still applying some compression to the steerer. You'd have to do some FEA to see exactly what shape it assumes, but that's not even the point. If the peak compression on the steerer is in line with the screws and the bit just north of the screw has no extension, then it is also the least stiff bit of steerer so it adopts the conical shape described. The radial compression is the same for the top and bottom screws, assuming the same tightening conditions, but the steerer compresses less at the bottom screw position because it has practically infinite extension either side of the peak loading. If you want to visualise, think of the lower screw creating a waist and the upper screw creating a neck

1 Attachment