Abstract: Carbon brake discs (14, 16) of an aircraft brake (10) include in opposing radial surfaces thereof circumferentially extending annular grooves (44, 46). Each annular groove (44, 46) may be disposed oppositely from an annular groove (44, 46) in the other radial surface of the respective disc (14, 16). Each annular groove (44, 46) extends radially from a respective adjacent axial edge (34, 36) of an adjacent disc (14, 16) and toward a peripheral area of the disc (14, 16) which is connected operatively with either a non-rotating axle (11) or a wheel supported rotatably on the axle (11). The annular grooves (44, 46) alter the contact pressure distribution between the discs (14, 16) and eliminate a portion of the disc (14, 16) wear surface which does not have continual contact with the mating wear surface of the adjacent disc (14, 16) and thereby minimize unstable rotor cycloidal motion.