A rotary assembly, comprising: - an outer sub-assembly comprising a first annular outer raceway and a second annular outer raceway which are centered on a common axis of revolution; - an inner sub-assembly comprising a first inner bearing ring (30, 34) on which a first inner raceway is formed, the first inner raceway having a raceway bottom diameter DI1, and a second inner bearing ring on which a second inner raceway is formed, the second inner raceway having a raceway bottom diameter DI2 larger than the raceway bottom diameter DI1 of the first inner raceway, the second inner bearing ring and the first inner bearing (30, 34) being fixed relative to each other; and - balls (16, 18) forming a first row of balls capable of rolling on the first outer raceway and the first inner raceway and a second row of balls capable of rolling on the second outer raceway and the second inner raceway for guiding the outer sub-assembly and the inner sub-assembly relative to each other in rotation about the axis of revolution, the balls of the first row of balls having a diameter DC1, a first pitch plane containing the centers of the balls of the first row of balls being located at a non-zero distance L from a second pitch plane containing the centers of the balls of the second row of balls; characterized in that: - the second inner bearing ring has an outer diameter (Φ), measured in a sectional plane perpendicular to the axis of revolution and located between the first pitch plane and the second pitch plane, at a measurement distance DM from the first pitch plane, which is greater than a given threshold value VS, where: { DM = 1,25 × DC 1 2 VS = sup 1,1 × DI 1; DI 1 + DC 1 2 - an outer sub-assembly comprising a first annular outer raceway and a second annular outer raceway which are centered on a common axis of revolution; - an inner sub-assembly comprising a first inner bearing ring (30, 34) on which a first inner raceway is formed, the first inner raceway having a raceway bottom diameter DI1, and a second inner bearing ring on which a second inner raceway is formed, the second inner raceway having a raceway bottom diameter DI2 larger than the raceway bottom diameter DI1 of the first inner raceway, the second inner bearing ring and the first inner bearing (30, 34) being fixed relative to each other; and - balls (16, 18) forming a first row of balls capable of rolling on the first outer raceway and the first inner raceway and a second row of balls capable of rolling on the second outer raceway and the second inner raceway for guiding the outer sub-assembly and the inner sub-assembly relative to each other in rotation about the axis of revolution, the balls of the first row of balls having a diameter DC1, a first pitch plane containing the centers of the balls of the first row of balls being located at a non-zero distance L from a second pitch plane containing the centers of the balls of the second row of balls; - the second inner bearing ring has an outer diameter (Φ), measured in a sectional plane perpendicular to the axis of revolution and located between the first pitch plane and the second pitch plane, at a measurement distance DM from the first pitch plane, which is greater than a given threshold value VS, where: