Abstract— This paper studies experimentally the oil pressures on the pad of thrust bearings under hydrodynamic lubrication. The smooth pad and the pad with circumferential grooves surface were considered. The configuration of a groove is V shape. The axial loads were applied to thrust bearings by the pneumatic system that controlled by the electronic board. The pressure transducer was used to measure the oil pressure distributions at the contact area. The oil pressures with varying both axial loads and runner velocities were presented in this paper. The hydrodynamic lubrication model for the smooth surface was used to predict the suitable condition for the testing bearing. The experimental results showed that the oil pressure distribution is affected by the axial load and angular velocity. The oil pressure, especially at the lower angular velocity and higher load, reduces when using the pad with circumferential v-grooves.