A seal assembly is disclosed for sealing a higher pressure fluid cavity from a lower pressure fluid cavity. The seal assembly comprises a runner mounting assembly, a circumferential ceramic runner carried by the runner mount assembly, and a carbon seal ring sealingly engaged to the runner. The runner mount assembly comprises an annular central junction portion radially spaced from the shaft, a pair of shaft engaging flanges, and a pair of runner engaging flanges. The runner is radially positioned between the runner engaging flanges of the runner mount assembly and the carbon seal ring.