Sorry the title was vague and this may not be the forum, but it's where I hang out and when I go to mechanics I usually get nothing. Maybe I should go to framebuilders... but I'll give it a shot here.
Say you want a new frame like a surly and you want to use a record 2 bolt seatpost in it. You will notice that the seat tube extends liberally above the TT-ST junction.
Knowing old frames were not like this, would the old seatposts be designed with this in mind (seeing as the lug joint is the stiffest point and the post should extend past it? Now if you were to put this record post in the LHT above and raise it to it's max height you would not have as much post extending past the Tt-st junction. I dare say that bit of seat tube is not so strong and I am wondering if it would be unsafe.
What do you guys think?
Surly sent me a rather useless reply to my inquiry saying the min. is a function of the seatpost. I did ask if there was a minimum amount of post that should be in the frame and they did not answer. I was very displeased with the reply. Obviously I am not worried about this post snapping I'm worried about the frame deforming.