I did not mention why we chose to change the frame. after adding a hydraulic motorcycle rack and the weight on the back with everything on it a short wheelbase could not cope with that added stress. Also the company that made the initial conversion without the rack did not extend the reinforcement forward enough to the frame drop to have the extra strength added to that point. With the Mexicano Roads with multiple speed bumps it proved to much for the frame and it cracked. The teeter totter effect was too much for the frame. With the longer wheelbase, the weight will be transferred more over the rear wheels and will be reinforced at the frame curvature. Also we are replacing the original frame with one the will be 1/16 inch thicker.
I don’t place fault with the original frame but rather the shorter wheelbase and the company not placing the reinforcement further up the frame. Also adding the rack afterward exacerbated the situation. I believe that if we didn’t add the rack that we would be still with the original frame. We had seven years with the conversion. I have no regrets in building the rack and realized that it would be experimental. Now with all the information and improvements I am confident that it will be great for years to come. Also the company that built the rack did not stabilize the rack properly and that added to the stress. There was too much movement back there. I had fixed that but it was not enough to stop the relentless stress from the rear. In other words the damage had already been done.
the stress was not from any twisting that I could see but the bouncing in the vertical plane.