A blade root shim comprises a base, a suction side shim wall, a pressure side shim wall, and a contact relief region. The base extends longitudinally between a leading shim end and a trailing shim end. The suction side shim wall extends along the base and corresponds to a suction side blade root bearing surface. The pressure side shim wall, spaced circumferentially apart from the suction shim wall, corresponds to a pressure side blade bearing surface. The contact relief region is formed into an upper wall portion of either the suction side shim wall or the pressure side shim wall.