•A test rig for the identification of force coefficients on gas bearing is proposed.•Stiffness and damping coefficients of Herringbone Grooved Journal Bearings are measured.•The Narrwo Groove Theory slighlty overestimates the stiffness and damping coefficients.•Stiffness and Damping coefficients are found to be linear against excitation amplitude. The Narrow Groove Theory (NGT) is commonly used to simulate and design grooved gas bearing. However, measurements of dynamic force coefficients of Herringbone Grooved Journal Bearings (HGJBs) is missing, hence the validation historic NGT has never been performed, despite its importance. A test rig was built in order to identify stiffness and damping coefficients of HGJBs of a rotor perturbed by piezo-electric shakers. Results indicate that the NGT captures the qualitative behavior of HGJB well but tends to overestimate the stiffness and damping coefficients by 23 and 29% respectively. Gravity led to a eccentricity ratio in excess of 15% without significant effect. The direct damping coefficient was found to be mildly non-linear with the excitation amplitude.