Choosing a bearing should be simple

Rosalyn Bearing 

“The size of a bearing for any application may be decided on the basis of its load carrying capacity in relation to the loads to be carried and the requirements regarding life and reliability. Generally, the basis static load rating and basic dynamic load rating are used to express the load carrying capacities of any bearing,” explains Ganesh Babu in his book Design of Machine Elements.

The catch is that the decision depends not only on knowing the demands of the application, but also understanding the way the bearings are rated in the first instance.

As well as their size and material, bearings can be categorised under their dynamic radial, static radial and axial load rating. However, these ratings can often be deceptive.

Realistically bearings should not be subjected to anywhere near these loads in normal applications.

To get the best life ratings from your bearings, limit the actual load to between six and twelve per cent of the bearing’s dynamic load rating. This load rating varies according to bearing material. For example, stainless steel bearings will support approximately 80 to 85 per cent of the load figures indicated for chrome steel bearings.