The rated dynamic load is one of the key parameters for measuring the dynamic load-carrying capacity and service life of radial spherical plain bearings. To accurately and rapidly determine the rated dynamic load of radial spherical plain bearings, this paper proposed a universal theoretical calculation model for the rated dynamic load of radial spherical plain bearings, based on the Archard wear theory and the displacement interference field model. The proposed model comprehensively considered the effects of bearing clearance, structural features, and operating mode on the magnitude of the rated dynamic load. By comparing the results from the theoretical model with existing data from studies, the accuracy of the model was demonstrated. Case studies with different bearing clearances show that, in addition to material and structural parameters, clearance is also a key factor that affects the dynamic load-carrying capacity of spherical plain bearings. The rated dynamic load decreases as the clearance increases. This theoretical model exhibits extensive applicability and can be extended to the design and selection of non-standardized spherical plain bearings, providing a crucial theoretical foundation for performance optimization and engineering applications of spherical plain bearings.