I will use 3Al2.5V alloy. If the main frame tube cannot be bent, I will have to use two sections to join together. But the shop manger told me that we should bend the tube first, then roll it into oval cross-section to increase vertical stiffness. Bending the boom tube and the rear stay should not be a problem. The design is similar to cruzbike S40. I am short with x-seam 38", therefore, need to raise the seat height a little. If this bike is ridable, I will build the next one with back rest angle 20 degrees. I weigh 55 Kg, therefore, don't need hefty tubing. The design parameters are very similar to my road bike's, forget about those super long wheel base and low head tube angle. I will go to Taiwan in March and purchase wheels and drive trains there, and order Thor seat from Poland.
The prepared mind leads to favorable chances.
Last edited by violini; 12-17-17 at 11:47 AM.