The saddle broke, so I had a welder fashion a clamp to go around the backbone tube, on which a modern saddle could be fitted. The welder only had the backbone and therefore made the flanges that clamped it in place too big, meaning the wheel could not turn around. I therefore took a file until the wheel turned freely, not taking into account that the backbone would flex somewhat and teh wheel was not completely round. I rode about a km before maximum flex of the backbone and highest point of the rim combined, blocking the wheel, sending me flying over the bars.