As Bjornorn writes down tube are mostly stretched. Some bikes just use a wire. Incidently that could also make for a better locking system that the stiff one wi

As Bjornorn writes down tube are mostly stretched. Some bikes just use a wire. Incidently that could also make for a better locking system that the stiff one with cuts. https://www.designboom.com/technology/kibisi-biomega-bos-8-speed-bicycle-06-20-2016/ https://www.designboom.com/technology/kibisi-biomega-bos-8-s...