The article identifies the causes of aeroelastic vibrations of suspensions on the arch bridge with the main span of more than 200 m. The study aims to determine the range of dangerous wind speeds and maximum amplitudes of these vibrations. This research is necessary due to intense vibrations of suspensions on the operated structure at wind speeds of 10÷15 m/s. The authors have studied models of bridge span structure and suspensions. Experimental tests as well as flow calculations using application packages have been carried out in the wind tunnel at NSTU. The study has provided verification of the vibration calculation method in the recently approved Russian regulations and comparison of the calculation with the current European method. It has been found that the cause of vibrations of the bridge suspensions is vortex-induced vibrations (VIV), while the central span of the bridge is not subject to aeroelastic vibrations. The experimental results coincide with the calculations and observations of the behavior of the suspensions of the bridge under moderate crosswind. The obtained results will be used in the future to develop methods of suspension vibration damping.