Originally Posted by Expatriate

I don't think the answer is as simple as any of the replies I have seen. If you start with a cheap tubing set of straight gauge tubing, there is a lot less labor in building the frame. When you get into thin wall, multi-butted, heat treated tubing, you don't hire just anyone to weld (or in some cases fillet braze) your framesets. I believe there's also a heating process after the frame is welded to restore certain properties inherent in the tubeset.