An exemplary elevator system includes an elevator car (22) having an integrated cabin and car frame structure including a platform thickness (T) between a floor surface in the cabin and a lowermost surface on a support beam used for supporting the car beneath the floor surface. A sheave assembly (26) is supported beneath the floor surface. The sheave assembly includes a plurality of sheaves and a plurality of subframe beams. The sheaves and subframe beams fit within the platform thickness (T) such that the subframe beams and the sheaves are no lower than the lowermost surface on the support beam. A plurality of isolation members are between the sheave assembly and the elevator car for isolating an interior of the cabin from vibrations associated with movement of the sheaves (26).