Well HV, you are asking for some confessions here..sortof...so here some of the results of my in-experience. or my path to education as I like to say!
ON the tube question, I used a mix of leftover stuff from previous airframe builds. Some 1 in .065 4130, some 1 in. .065 DOM 1030, some 1 in. .058 4130. What I think I learned is, .058 4130 would have been sufficient for all..and the 4130 bends easier than the DOM1030. Next build will be all 4130..might even drop to .049 on the next to save a little weight..dunno yet. After I slapped together an extended wheelbase /lowered seat pedal frame to see if I could do it, and test the dimensions I had in mind (sized for my wife, and sort of a proof of concept)..and it rode down the road sideways..I decided I needed a jig, so I built one..which is seen in the 2 pics. The jig helped keep the wheels/axles/ fork/neck/backbone/rear triangle straight and gave me some fixed points to measure from for symmetry. Worked much better. I unbderstand about the regs, and I debated on makeing this machine road legal for quite awhile, but decided it would just compromise the mission requirements and I kept on coming back to the point you made..We have 2 perfectly good motorcycles for riding on the road, and they dont do worth a durn in a campground going real slow. I even bought a Old Honda Twinstar 200 and restored it and used it for campground duty..but riding double in first gear (even with a smaller front sprocket) it just didnt fit the bill..hard to handle slow and engine would get hot.) So the inabilities of motorcycles was actually the justification to take on this project...why try and make my MB run like a motorcycle? So I didnt. We just wanted bikes we didnt have to pedal.
