Hi Jürgen and all, Finally finished my bike mostly. It has a 120 cm wheelbase, 65 degrees pivot angle (intended it to be 65degr, but need to measure it to have an exact value), 2 x 20" wheels, detachable pivot, adjustable seat angle, 3-speed hub gear with coaster brake. It weighs now 11.45 kg, will add some sort of steering rod and a rear brake, but I don't expect it to be more than 13 kg. Could have come out it even lighter if using thinner tubing (this is 1.5 mm wall thickness SS tubing I had left from other projects and used it up now). Will make some detailed pics of the parts and upload them to a picasa album, but here are 2 pics for now: https://plus.google.com/photos/115292543199069523585/albums/5875961104825681585 Just tried it in my garage, and was surprised that I was able to ride it for approx. 8 m at the first try. Will take it to town to a large empty parking lot and see how I can handle it. Looks very promising for now though. All the best and thank you for all. Tiha