Low torque radial shaft seal assembly

A shaft seal assembly, comprising:

• an annular metal case having an annular leg extending radially inwardly toward a central axis of the seal assembly to a free end, said leg having opposite oil and air sides facing respective oil and air sides of said seal assembly;
• and
• an elastomeric material bonded to said leg, said elastomeric material forming a main body adjacent said free end of said leg and an annular primary seal lip radially inwardly from said main body, said primary seal lip having a thickness extending between a radially outwardly facing backing surface and a radially inwardly facing sealing surface, said sealing surface extending along a length of said primary seal lip from an air side end to a free oil side end and being configured to extend parallel to said central axis along said length against a shaft running surface, said air side end being attached to an annular bridge formed from said elastomeric material via a first hinge and said bridge being operably attached to said main body via a second hinge, said bridge having opposite sides extending across a thickness of said bridge, said first hinge and second hinge each having a thickness less than said thickness of said bridge and said first hinge having a thickness less than said thickness of said primary seal lip.