Designed to increase traction to rear tires, third link assembly uses interchangeable polyurethane bushings (sold separately, two required) to absorb energy under acceleration and braking. Bushings can be quickly changed to adjust to changing track conditions. Assembly is 2-1/4" wide x 3" tall and has a 3/4"-16 RH chrome moly stud for attaching a suspension tube. 3/4" I.D. inner steel bushings are stepped to keep link centered in poly bushings. A good starting point is a 70 durometer acceleration bushing and 90 durometer brake bushing.