Polyurethane also has longer life expectancy than rubber, which should be factored in when assessing cost. Speaking of durability, the breakdown and compaction of the rubber is further aided by exposure to oil, salt, ozone, and a host of other elements. Before long, the bushings are as hard as a rock or soft as taffy, depending on where they are on the vehicle and what conditions they have been exposed to. Energy Suspension's award winning new sway bar bushing design allows for periodic maintainence along with the rest of the suspension. The new design incorporates Zerk fittings with an inner channeling system that encapsulates grease all along the surface of the bushing and section of the bar it contacts.
Polyurethane is unaffected by petroleum-based solvents and atmospheric contaminants.
Between these extremes lies the perfect formula for suspension-bushing material. When formulated and designed correctly, polyurethane bushings will be the last bushings you put on the vehicle. Rubber deterioration also compounds the original vacillation of the suspension. This works to a certain degree when the rubber is new. As it starts to age, the ability to rebound back to the original shape diminishes.