I've been working on this tall bike for the last few days and I don't seem to have the handling down right. When it's clamped under this set up turning the bars on the top bike will force its bottom bracket off the post. I'm sure if I welded it like this then it would either be really hard to turn to the point of probably breaking my welds. What am I doing wrong / how can I get it to work?? Any help is greatly appreciated, this is my first tall and not sure exactly how the pivot points work.