UMI's on car adjustable lower control arms utilize our Roto-Joint technology for a bind free performance, quiet ride quality, and also offer on car adjustment. The control arms can be adjusted longer or shorter moving the rear end back or forward to squeeze those larger tires in the fender wells. Adjustable control arms are also recommended for most aftermarket rear end installs to center the rear end and prevent tire rubbing. The installedRoto-Joint is a pivot ball lined with a greaseable delrin race designed to offer 28 degrees of total unrestricted movement, more than adequate for a bind free, low friction operation. The Roto-Joint design improves performance over the factory rubber and aftermarket polyurethane bushings by allowing the suspension to articulate correctly, and provide precision handling. This control arm set features polyurethane bushings on one end and UMI’s spherical Roto-Joint on the other end. This set-up is designed for street performance and street enthusiast. The polyurethane bushing end is designed to be bolted to the vehicle chassis side while the Roto-Joint attaches to the rear end side. Since the polyurethane bushings are softer they are designed to absorb more road noise and shock before it enters the passenger compartment of the vehicle. All bushing ends and Roto-Joints are greaseable and low maintenance making an excellent street setup for your cruiser!