A car’s suspension quite literally and figuratively rides on its bushings. Deciding on installing rubber bushings vs. polyurethane ones is no less a decision than choosing the difference between a smoother, quieter ride compared to a better feel in how the car handles and steers. There is that much of a difference. Both rubber and polyurethane are elastomeric polymer materials that share a few similar properties. The two materials are nevertheless distinct from one another and formulated to achieve different results in their applications. This is especially true when it comes to choosing between the two materials for bushings.
Bushings are indispensable components that ensure that a car’s suspension remains sound. Designed to reduce friction and absorb shock between two surfaces, bushings provide the needed cushion for your car when driving over bumpy roads. They provide noise and vibration reduction, and also control the degree of movement in the steering joints that aid in preventing any swaying sensation when turning.
Bushings are located in all the related suspension and steering parts of a vehicle—control arms, ball joints, tie rods, stabilizer or sway bars, shock absorbers, and strut mounts. They are also used to reduce friction in the engine and transmission mounts. Due to varying weight loads carried by vehicles as well as the general stress of frequent movement, age, heat, cold, exposure to chemicals, lubricants and in some areas, road salt, bushings will eventually crack, wear out, and become ineffective.
Suspension Material Choices
Polyurethane is an exceptionally versatile, durable, flexible, adaptable, and resilient elastomeric material. Its mechanical properties give it the strength of wood and rigid plastic, but the elasticity of rubber. It’s used in components and parts for automobiles, medical devices, footwear, adhesives, sealants, and flooring but also as the absorbing foam found in mattresses and upholstery.
Rubber in its synthetic form, like polyurethane, is an elastomer. It’s known for its elasticity, durability, toughness and resilience. It’s widely synonymous with tires for the main reason that it is the basic material used in its manufacture. Half of all rubber production goes to tires. A good portion of the other half goes in the manufacturing of parts and components for the automotive sector—components like bushings and mountings.
Difference Between Rubber Bushings vs. Polyurethane for Suspension
The difference between rubber bushings vs. polyurethane ones for a vehicle’s suspension relate to the mechanical properties offered by each. Polyurethane is generally more durable than rubber, and is well-suited for applications such as bushings, ones that require continual exposure to stress or constant stretching, yet offers a degree of flex, with plenty of strength. Rubber, on the other hand, is best known for a single mechanical property—absorption. It is the most effective material for absorbing vibrations (tires are not made from polyurethane for a reason).
When it comes to choosing between the two materials for a car’s suspension, rubber bushings are more effective at dampening and absorbing road noise and vibrations on hard or uneven surfaces. Rubber bushings offer a quieter, smoother ride, and are typically used as original equipment by the manufacturer. The latter may be in part due to the lower cost of rubber over polyurethane. The production of polyurethane is a complex, and expansive, process.
On the other hand, because of that complex process, polyurethane is a much harder, rigid material that lasts longer than rubber. Harder bushings give drivers a more enhanced feel for the road, and by extension, the rigidity increases the control the driver has over the vehicle. The rigidity also reduces the swaying sensation that occurs with softer rubber bushings, but lessens the dampening effect that rubber bushings provide. The car will feel a lot more of the road, and the drive will be nosier.
When choosing a bushing for an automobile, if you’re driving is general purpose highway commuting, select a rubber bushing for a smoother, quieter ride. If your drive is taking you on roads that require a degree of handling, a polyurethane bushing offers more control in steering and a better feel for the road. In the end, it’s best to choose the bushing that’s better suited for the conditions of the roads.