Originally Posted by
CliffordK
You might find this thread interesting:
Modifying a frame
Anyway, the user had a most unique tandem with a forward sloping top tube, and a tall mast on the seatpost similar to the OP's. He had to lower the seat by about 2".
However, the post used a unique half-moon lock in a tube.
So, that post lock was simply moved downward.
I went to the link, and in viewing the repairs it seems to me that 1) the tube containing the locking stuff is steel, and 2) other pics on that post show the dropouts on this bike being steel, and 3) the weld bead on the relocated tube looks pretty small (certainly not adequate for an weld in aluminum, and 4) the fix was obviously not post-weld heat treated. So I suspect that its steel. It's a clever mod, and in steel easily done. In aluminum, on a frame that's already broken, not so much.
Upon further research, the tandem is a Counterpoint Tandem Opus, which has a steel frame. (Interesting tandem: recumbent in front, upright seat in rear). So not applicable to the Al frame repair discussion because if you did that mod, you'd still have to post weld heat treat the whole frame, or you'd expect another crack in the area of the weld quite shortly.
https://aroundthecycle.com/products/...=8370188943420