A bearing is a device to allow relative motion between two or more parts, typically making rotating or linear movement.
Plain bore wheels in castors are suitable for light to medium loads and where some movement is required.
Roller bearings in castor wheels reduce the effort needed to move medium to quite heavy loads
Ball Journal bearings in castor wheels are longer lasting. Ball journal bearings are essential for constant moving applications, omitting heavy towing operations.
Top Hat Bushes are supplied if ball beairngs are to be used