How powerful is a 6v servo motor?
A servo motor isn’t really a good choice to power the main wheel of a scooter. Servos are specifically designed to be very precise (as in, “turn exactly 3.7 rotations”), for a drive motor all you need is “turn pretty hard until you release the throttle.” The other problem I see is that kg/cm is not a unit of torque. N·m is a unit of torque… the spec they have doesn’t even make sense.