Polyurethane bushings for BMW 3 Series E30 / inner and outer trailing arm mounts L + R — TA Technix

The original bushing is made of rubber: it filters well, but deforms under load. When cornering or braking, the arm moves by a few millimetres and the alignment changes during the manoeuvre - this is the vagueness 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, there is more road noise and vibration in the cabin, especially when cold.