Suspension bushes are fitted to cars at all points where the vehicle chassis is joined to a moving suspension component. They are fitted to provide a noise and vibration absorbing barrier between the road and you.
Rubber has traditionally been used for automotive suspension bushes. It has the advantages of low cost, it is easy to work with, it can be used for a wide variety of applications and is able to provide a reasonable level of insulation between steel components. However, it has some significant disadvantages:
All this causes the rubber to start to lose its elasticity and as importantly its resilience. In time rubber will lose the shape it was designed to be. The car's suspension components start to move to a position different from the ideal, with a loss of handling precision, predictability and accelerated wear of other components and tyres.
In contrast, polyurethanes, especially those manufactured using cold pour / thermo setting processes, can be resistant to all of these problems and retain their original shape. The result is suspension bushes which will last a lot longer than rubber and will also perform.