Why are skating trucks called trucks?

Answer 1

Etymology of the word "truck" probably comes from a shortening of the word "truckle". Truckle is related to the Latin word trochus, which means "iron hoop" or "wheel". Since the axles on skates were originally small, iron wheels, that is probably why they are called trucks.

Answer 2

Primarily trucks are axles to mount your wheels . . they are also giving the rider the ability to steer and add ground clearence as needed for the type of skating that is done..