Research has been undertaken into the question of comfort on a standard 'utility' bicycle. Most ergonomics studies on bicycles so far have focused on biomechanical and physiological factors influencing the efficiency of road racing. The actual use of a utility bicycle has been neglected in this research. One of the reasons, especially in studying sitting comfort on bicycles, is that conclusions must be based on subjective measurements. In the study described in this paper, the main focus is on the measurement of cyclists' preferences in a dynamic way, compared to physical data. A pilot study and laboratory experiment were carried out to investigate, among other aspects of cycling comfort, the validity of existing rules of thumb for bicycle fitting. The data, collected with the aid of two specially designed ergonomics measuring stations and an 'interactive remote-control bicycle simulator', indicate that these rules of thumb are questionable. By way of improving the fit between cyclist and machine (and assisting bicycle shopkeepers to select the right bicycle for their customers), a commercial bicycle fitting system has been proposed and developed for production.