Ahh, seatstays. Now here’s a bit of interesting fact – if you are building one-off custom titanium frames, you can’t
actually measure and draw out the exact dimensions of your seatstays due to the complex process of chemical changes when welding titanium. I’ve always thought titanium was one of the coolest metals (besides mercury, but at least titanium is safe) due to its chemical nature. So…geeky insider peek – I was a chemistry minor in undergrad and should have been a major because I LOVE chemistry. It is just sooooo fascinating. So anyway, titanium likes to return to its original shape when it’s bent unless you chemical change it, say via adding heat through the welding process. To be really basic in my description (I apologize to you titanium experts out there), this makes titanium such a great material for bicycles because you can put it through a lot of stress and it likes to go back to its original shape (post-chemical change through welding). That said, when adding heat and forcing chemical change, that means there will be some torquing and shrinking, so when you get to the point of adding your seatstays, you really can’t predict how much your titanium frame will have altered its shape, so there is a little bit of thumb-to-the-wind, involved. I don’t know all the details except I heard there was string and measuring involved. When it’s all said and done, though, there’s a lot of bending back into shape that has to happen before the frame is ride-worthy.