Hydrodynamic retarder

The hydrodynamic retarder for a motor vehicle has a rotor and stator blade wheel, wherein at least one blade (1) of the stator (9) and/or the rotor (5) consists of two segments, wherein the first segment (2) is directly connected to the stator (4) and/or the rotor (5) and the second segment (3) is rotatably mounted, wherein the axis of rotation (7) is selected such that the rotatable blade segment (3) in braking operation can rotate parallel to the stationary blade (2) by the fluid flow and is supported thereon, and in non-braking operation can be reset to a position that obstructs the fluid flow.