For more than 50 years, rubber bushings have been the standard for automotive suspensions. Low cost and a relatively maintenance-free performance made them the commercial choice for bushings. However, the search for a more rigid bushing with improved performance has many considering urethane bushings.
The suspension bushing transfers the shifting loads of the vehicle from the body to the tires through the suspension. Rubber has long been the material of choice for these bushings as it helps to mitigate vibration, has good wear resistance and rarely requires lubrication. However, the softness of rubber can allow for deflection of the bushing when put under significant load in sharp corners. This can result in unwanted loss of traction in high-performance applications.
Urethane, however, can have more than 10 times the load-bearing capacity of most standard rubbers. The greater strength and stiffness of urethane bushings mitigates the effect of load on steering as the bushing has only minimal deformation.
Although some lubrication is desirable to minimize sounds and binding, urethane bushings are becoming a more popular option for performance drivers or those seeking to tighten up the feel of their suspension through more aggressive turns.
