After repeated use, most vertical strap roller hangers will start to tilt due to the force of the hangers striking against the track stops.
Goldberg Brothers Roller Hanger Stabilizers mount to the top of the door, behind both hangers. They significantly reduce or even eliminate hanger tilt by supporting the hangers and taking much of the force of impact away from the hanger mounting bolts.
Roller Hanger Stabilizers keep your barn doors looking as good as when they were first installed.