A new test rig was developed to measure the friction/traction of lubricating films in nonconformal contacts.The construction of the apparatus and test scheme were introduced.Employing two PAO lubricants,friction data were acquired in realtime under simple sliding conditions.The variations of friction coefficient with speeding up and down were observed.By analyzing the friction coefficient curves,lubrication regimes can be recognized,suggesting this device can be used to assess the lubrication mechanism and the properties of lubricant and rubbing surfaces.Moreover,the measurements may be beneficial to confirm and improve the lubrication models.