A wheelset bearing for the wheelset of a rail vehicle having an internally mounted truck that includes one bearing housing per side of the wheelset that encloses the wheelset bearing for the wheelset, where the wheelset bearing and bearing housing are within the wheels in an installed state and a torsion spring serves as a roll stabilizer that is connected to the bearing housing such that the torsion springs are rigidly connected to one bearing housing each on the two ends thereof (without interconnection of draw-pressure rods) so as to implement roll stabilization for the wheelsets in a manner that is as technically simple as possible.