A caster should always travel firmly on the floor. Yet that is mostly pure theory. casters always briefly lose contact with the floor on uneven surfaces, at door thresholds, tracks and also in potholes. They are suddenly overloaded or only three of the four casters touch the ground, and have to bear the whole load. This must be taken into consideration when calculating the load capacity. The following formula therefore provides the necessary safety reserves: Tare-weight of the device plus load divided by three. All load capacities given in this catalogue have been determined according to EN 12526 to 12533 for dynamic loading. Additional static load-bearing capacity information is given on our homepage.