Let's start the cargo bike using a german "klapprad". According to my father, these bikes are stronger than usual and fit perfectly our needs:
- thick metal easy to solder
- the bike can be splitted into 2 parts, the junction being horizontal
- the rear hub contains an automatic 2 speed gearbox "duomatic" with back pedal brakes
The idea is to solder a 1 meter metal bar rigth in the middle and deport the direction.