Here is a system I designed to do just that. The smaller diameter of the gear reduces the travel of the wheel while increasing pulling torque. The PLM wheel motors are, in this way, easily capable of a thousand lbs (453 kg) of lift each, while still being able to achieve horizontal speeds in excess of 50 mph (80 k/h)
This system works because the wheels can be independently disengaged (powered down) during the transition to gear/tire drive or held to an RPM, which is consistent with the vehicle speed, rather than the speed of the other wheels. Therefore one wheel (which is gear engaged) can be rotating at a different RPM than a wheel whose tire is still engaged. The final effect is the same as motor, transmission and clutch, all with no moving parts except the wheels.