The Uk site of motorized trailer for atv show a trailer with 2axle in the middle, one of them is hydraulic drived, maybe it is the reason why they put 2000kg on the trailer, perhaps it don't make too much weight on the tongue. The system i have imagined is a disconectable powered axle with a little dumper upside, when connected my quad will be changed in 6x6 quad, and 2x4 or 4x4 the rest of the time. M'y question is how to create the power of the axle, "a pony motor", an electric motor, an hydrostatic system. I think i can put on and off the axle drive with a system like automatic brake on car trailer. When the tongue is tense, the axle is drived, and when the tongue in compression, the drive is off. Anyone had seen this type of system yet?