Polyurethane bushings for BMW 3 Series E30 / E36 Compact / rear anti-roll bar mount with 12 mm Ø — 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 geometry 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. The trade-off is more road noise and vibrations in the cabin, especially when cold.