Concern about molybdenum lubricant on stepper motors. Momentum 0.35Nm will be in this case smaller. Needs (at least for wheels) to use something to increase momentum. Previous decision not to use gears make it difficult. Was considered to use some alternative way. If wheels-motor system will be controlled by microprocessor it is possible to use springs and controllable oscillation movements to accumulate energy in springs with releasing it (energy). Oscillation frequency in this case can be controlled by springs parameters.