If the radial shaft seal is in a system that is serviced often, then the type of static O.D. needs to be considered. Metal press-fit O.D.s require low installation forces but are difficult to remove. There are also small particles of the bore removed when a metal press-fit is uninstalled. If an application required a dozen replacements over the life of the system, a metal press-fit would not be a proper choice. If ease of removal is important and the service may take place outside of a service shop then a pry flange may need to be incorporated into the design. These parameters should be considered and addressed early in the design process to save money and time for the aftermarket.