Recently a demand for maintenance-free is increaing for mechanical components. We have already developed spherical plain bearings fitted with liners for railroad vehicles, which are now used in such places as anti-rolling equipments or longitudinal dampers in the vehicles for The New Tokaido Line. On the other hand, in construction machines or the like, development of a spherical bearing with high impact strength, resistance to high contact pressure and high resistance against muddy water is demanded. Investigations into anti-wear performance as well as creep resistance of various liner materials were made. It was found that polyimide resin with some fillers is the most superior.