Not quite sure the place is the right one to ask, but i'll try my luck.
I have a frameset that have a clamp of the seatpost that probably not the most robust design:
There is a screw at the end of the top tube that lock the seatpost in place.
A closer look:
I was afraid to overtighten it, and at the end of a ride it slipped and the seatpost went down the seat tube (hopefully, it was at the end of the ride near my place). I re-set the height and tighten the screw quite a bit more, and it hasn't moved since (but I've not rode it much).
Is there any solution to this? I have a framebuilding company not far, so I'll probably ask them but as it is on appointment only and with a 45mn drive, I reckoned it was interesting to ask on here before.
What would be the potential solutions to have a better seatpost holding solution?
Change the complete seat tube (but would be a pain I believe since it go through the top tube)?
Manufacture a seatpost with an expander (like a stem)?
Buy a steel seatpost (if that's even a thing), tighten the screw hard and not worry about it?
Thanks in advance for any ideas!