There are mainly two reasons why some people like polyurethane automotive bushings.
Polyurethane bushings have a longer service life
For all polyurethanes, the situation may be different. Well-designed polyurethane bushings can last for a lifetime. The manufacturers of these polyurethane bushings even provide lifetime warranty services. Polyurethane bushings have many key features, especially their service life, which also include their self-lubricating polyurethane materials, and specially-designed lubricating grease retaining grooves.
Because of the molecular structure, the polyurethane bushings have high tear resistance. This is why they must be lubricated with grease before installation, otherwise, they may encounter long-term problems due to casing tearing.
Polyurethane bushing handling is more accurate
In addition to the durability and life-long warranty of the polyurethane bushing, its manipulation is the primary concern of any car owners who want to buy polyurethane bushings. In order to endow the car with the best handling, it must have a very precise calibration, which is different between the vehicles (and from the platform to the platform); a soft front swing rod helps the car grasp the ground when the car body tilts, and a hard rear swing rod can help the car rotate at the corner. This is the role of rigid polyurethane bushing.
If you want to keep having a very accurate suspension system, you have to remove the bending, weld the chassis parts, prevent the roll cage reinforcement, and replace all the suspension bushings with polyurethane bushings, even the solid plastic or metal. Finally, the casing deflection will make your suspension settings lose effectiveness.