The bins range in size, from 12T to 38T in most cases. Single axle bins usually can only handle a maximum of 20T of grain, with excess weight placing undue strain on the axle, potentially causing failure, especially on rough terrain. Bins above a capacity of 20T, tend to feature a "walking beam" chassis. This chassis design features an independent axle setup, allowing the bin to smoothly travel across ditches and divets, as well as more easily access fields where the road is higher than the field level. It also allows the load to be evenly distributed along the length of the chassis, further reducing the risk of axle failure when traveling over rough terrain, particularly with a full bin.