These are the following things to consider when choosing a castor.
- Wheel Diameter: The nominal diameter of the outside of the wheel, this typically describes the basic size of the castor (i.e. a 150mm wheel diameter castor is typically referred to as a 150 castor).
- Swivel Radius: The distance from the center of the fastening to the outer most point of the caster. This specifies the minimum clearance required for a mounted caster to swivel a full 360 degrees.
- Mounting Height: The vertical distance between the bottom of the wheel and the mounting point of the unit.
- Load Rating: The load a castor is designed to carry on a continuous basis. Load is assigned on a per caster basis. To determine the load based on the number of casters on a unit, divide the total weight by the number of castors.