Car bushings are small suspension components made from either rubber or polyurethane that provide cushioning, isolate vibration and reduce friction between the vehicle's metal parts. Control arm bushings and sway bar bushings are the most common car bushings.
The hardness or durometer of rubber and polyurethane bushings may vary. Rubber bushings do not squeak, while poly bushings do if not properly oiled. Bushings can flex, and flexing affects the steering and general feel of the car. Softer bushings give a quiet and smooth ride but may also cause poor steering control. Harder bushings are more rigid and provide better car control but are noisier. Deterioration of bushings softens and damages the rubber or polyurethane. The car feels loose, steering becomes uncontrollable, and friction between vehicle parts increases, leading to noise and damage.
Rubber is soft by nature and allows the vehicle mounts to absorb vehicle vibrations and noise. In most cases, customers have reported increased noise due to polyurethane mounts. Polyurethane bushings last longer than rubber bushings, and they have better-standing power against chemicals, oil and road debris. They also handle compression and load better, and they perform better by reducing further sloppiness in suspension performance due to damaged, worn or missing bushings.