An agricultural vehicle including a chassis and a threshing system supported by the chassis. The threshing system includes a rotor, a housing surrounding at least a portion of the rotor and including at least one concave, and a concave adjustment and suspension device connected to the housing and configured for adjusting a position of the concave frame and relieving an impact force acting on the at least one concave. The concave adjustment and suspension device includes a torsion bar, a drive operably coupled to the main section of the torsion bar and configured for rotating the torsion bar to adjust the position of the concave frame, and at least one pneumatic spring mounted to the torsion bar and configured for compressing to relieve the impact force acting on the at least one concave.