Offset
Castors can be divided into non-swivelling fixed castors, which give the castor its directional stability, and vertically rotating swivel castors that enable manoeuvring. Manoeuvrability is achieved by connecting a steering fork to the fitting element of the wheel via a swivel bearing. There is a horizontal distance between the wheel axle and the swivel bearing – this distance is called the offset (F).
When transport equipment is being moved, the castor or swivel resistance must be overcome. This resistance is influenced by several factors, including not only the tread, the tread material hardness and the substrate but also the offset. For this reason, the right offset must be taken into account when selecting a castor. It is then possible to swivel the castors without using any aids. When moving straight ahead, the offset ensures stable running characteristics. It also influences the load-bearing capacity of the castors and the amount of wear on the back bearing.
Rule of thumb for the offset
Generally speaking, swivel castors with a large offset have a lower load-bearing capacity and more wear on the back bearing, but ensure smooth running characteristics. With a smaller offset, however, the load-bearing capacity is higher and there is less wear on the back bearing. However, the running performance is not as smooth. For the respective requirements, the optimum projection of the castor housing must therefore be selected.
We will be happy to advise you on the subject and help you find the castors with the right offset for your transport equipment. Get in touch with our experienced team!