A model for self-excited vibrations of a single-disk asymmetric rotor with short sliding bearings is proposed, which is reduced to a system of four ordinary differential equations of the second order. The obtained dynamic system is described by the Shaw-Pierre nonlinear normal modes.Keywords: short sliding bearings, the Reynolds equation, nonlinear normal modes of vibration. Introduction. Self-excited vibrations in the rotor system can occur due to interaction between oil film of the bearing and the rotor shaft pivot (journal). It is shown in [1] that such interaction results in failure of some rotor systems. At present, modern analytical and numerical methods of the nonlinear dynamics [2] are widely used for studying vibrations in rotor systems. The analytical results which describe the pressure of the oil film in the bearings were obtained in [3]. The asymptotic solution to the Reynolds equation was obtained using the variational approach in [4]. Stability of the pivot rotating in the bearing was considered in [5]. The model describing the pressure distribution in the oil film of short sliding bearings was proposed in [6], where the impact of oil film inertia forces on the pressure was studied. The authors [7] use the asymptotic methods for studying self-excited vibrations in rotors. Forced vibrations of rotor with account for oil film in short sliding bearings were analyzed in [8], whereas the rotor dynamics was described using the design model consisting of elastic shaft with three discrete lumps.Nowadays, nonlinear normal modes of vibrations are considered to be the most effective approaches to the theory of nonlinear mechanical vibrations used for analyzing both natural and forced vibrations [9-11].A new model for self-excited vibrations of the single-disk asymmetric rotor in short sliding bearings is proposed in this study. Pressure in the oil film is described using the model of short sliding bearing. To study self-excited vibrations of rotor, modified method of the nonlinear normal modes is given.Equations of Motion for the System. Let us consider the dynamics of the rigid disk which is mounted on the rotating shaft in short sliding bearings (Fig. 1). When the shaft pivot vibrates, pivots A and B (Fig. 1) move. These motions are described by generalized coordinates (x y