Hello All.
I have been asked to shorten a seat tube from 24" to 17-1/2". I have no experience modifying or building bike frames, but do have lots of fabrication and welding experience. I have a few questions I would like input on before I agree to do this work...1) Is it acceptable to miter the top tube (degree to be calculated) just rear of the head tube and forward of the seat tube and perform butt welds to change the angle of the top tube? Or would it be better to remove the existing welds and re-do the original junctions? 2) I would like to remove a chunk at the middle of the seat tube so that I do not have to mess with the seat post clamp or worry about the seat post not fitting. 3) Obviously the seat stay angle must be changed also while maintaining axle center to brake mounting dimensions. This should not be much of a problem. The original frame joints are all butt-tig welded and I believe it is chrome-moly tubing.Thanks in advance for any advice.
P.S. No need to comment on any liability issues.