Polyurethane bushings for BMW 3 Series E30 / mount between thrust arm and rear subframe — TA Technix

The original bushing is made of rubber: it filters vibrations well, but it deforms under load. When cornering or braking, the arm moves by a few millimeters and the alignment changes during the maneuver - this is the slop between the steering wheel and the wheels.

Polyurethane deforms much less: the connection becomes precise and repeatable, and the car responds at the same point every time. In return, more road noise and vibrations enter the cabin, especially when cold.