A bogie is the simplest type of tracked suspension. it is simply a beam that has one road wheel on either end; this beam freely rotates around a central axle connected to the vehicle, as shown in Figure 16-19. As the road wheels on the bogie go up and down, only half of their travel is transferred to the bogie's central axle-for example, when a wheel moves upward by 2 studs, the axle will only move upward by 1, as shown in Figure 16-20. So bogies provide reasonably good flotation, but they don't reduce shock.