A ring binder mechanism (100) has a resilient polymeric housing (102). The housing (102) has a central portion (148) and lateral sides (150) extending downwardly along either side of the central portion. A metal ring support (128) is supported between the lateral sides for movement relative to the housing (102). Each of a plurality of rings (104) includes a first ring member mounted on the ring support for movement therewith to open and close the rings. The housing (102) applies a spring force biasing the ring support (128) toward the open position when the first ring member is proximate its open position and biasing the ring support (128) to the closed position when the first ring member is proximate its closed position. The housing spring (102) force is the only spring force applied to the ring support (128) that moves the ring support (128).
