The article deals with the development of a more accurate method for determining certain parameters of a bearing in the early stages of the engineering design process. Using the traditional approach, the parameters of the given parts are estimated by experience. Another method is to make a simple estimation of basic static or basic dynamic load rating, which is inaccurate if is applied. Following this step a potential bearing is chosen from a catalogue and is recalculated or replaced, which provides the inputs for optimization. The approach described in this paper can be used to estimate the mentioned parameters with regards to the load value and its duration.