An embodiment of a high-mobility vehicle comprises a vehicle body, a track assembly attached to the vehicle body, arms pivotally attached to the vehicle body, and trackless drive wheels mounted on distal ends of the arms. Another embodiment of a high-mobility vehicle comprises a vehicle chassis, right and left drive motors attached to the vehicle chassis, right and left power transmission mechanisms having high torque and low torque sets of gears, track assemblies coupled to the high torque sets of gears, and trackless drive wheels coupled to the low torque sets of gears.