A chassis testing unit (2) according to the present invention, in particular a shock absorber testing unit, for a vehicle on a test set-up (4) includes at least one correlation sensor (14-18), having an associated lens, situated at the side of the test set-up (4). The correlation sensor (14-18) is directed toward the test set-up (4), and is designed to detect a time sequence of images of a section of a motor vehicle (6), in particular of the body of the motor vehicle (6) and of the motor vehicle wheel, moving on the test set-up (4), and to determine directional velocity components therefrom. The chassis testing unit also includes a data processing unit which is connected to the correlation sensor or correlation sensors (14-18), and which is designed to determine the motion of the motor vehicle, in particular of the body of the motor vehicle (6) and of the motor vehicle wheel, on the basis of the directional velocity components of the correlation sensor or correlation sensors (14-18).