Selection Criteria for Wheels and Castors
The following criteria may help you to select the right wheel or castor. In case of doubt, a practical test might be appropriate. All information, especially regarding load capacity, but also for technical support in spoken and written, is given in all conscience, but need to be seen only as advises. These indications do not release the user from own tests regarding the suitability of the product according to the actual application.
Tractive - and rolling resistance
The tractive resistance is the force, necessary to get a resting wheel moving. The rolling resistance is the power that is necessary to keep a moving wheel going. Both resistances depend on the size of the wheel, the kind of coating and the bearing as well as the composition of the floor surface.
Tare + load = maximum load capacity. The load capacity for a vehicle with four wheels should be divided by three because not all four wheels will carry the load equally (uneven pavement etc.) at all times. The load rating mentioned in our catalogue refers to a maximum speed of 4 km/h on a smooth, even and clean surface at a temperature of about 20° C.
Caused by driving through potholes and crossing railway tracks or thresholds etc., the wheels and castors sometimes receive impacts or blows that exceeds the load rating and can result in damage or ultimate failure. If this cannot be avoided, it is recommended to select wheels with an elastic coating and a big diameter and to choose a castor with a load capacity calculated with most possible load capacity reserves.
Surface condition of the floor
The condition of the floor surface is an important criterion for the choice of the wheel material. For sensitive floors (tiles, ceramic etc.) we recommend wheels with elastic coating e.g. polyurethane or Vulkollan®, solid rubber or elastic solid rubber. Furthermore, it should be taken into account that black solid rubber wheels may leave black marks on the floor. If this needs to be avoided we offer special wheels (in blue or blue-grey). For more solid floors wheels with a low rolling resistance like steel, polyamide or cast iron wheels can be used. The result: smoother rolling and a higher load capacity.
Environmental influences are also important for choosing the right wheel or castor. For a detailed overview concerning the chemical resistance of the different materials please click here. In wet conditions a material that does not rust should be chosen and for high temperatures we offer heat resistant wheels.
* Vulkollan® = registered trademark of Bayer AG, Leverkusen