The Ultimate Performance Thrust bearing assembly registers between the spring perch or adjuster and the spring. The main purpose for using thrust bearings is to eliminate the binding of the spring as it compresses through travel. As a spring compresses it twists, thus causing bind on the shock. This is eliminated with the use of the bearings. They are also beneficial in making ride height and corner balancing adjustments easier when there is load on the spring. These assemblies are available for both 2.25″ ID springs and 2.50″ ID springs.