In this contribution, a given test rig of a rotor system with journal bearing is validated by using simulation models with different levels of detail. A special focus is placed on the misalignment between rotor and bearing axis. It is shown, how to consider misalignment in the numeric calculation of the bearing forces as well as in the modeling of the rotor system. With a model of the LAVAL rotor, the misalignment in the test rig is identified by measuring and simulating relative equilibrium positions of the rotor in the bearing at different rotational speeds. A measured rotor orbit due to unbalance is used to compare simulation results of different complex rotor models and discuss their accuracy and efficiency.