82-02 Fbody UMI Performance On Car Adjustable Rear Control Arms (Poly/Roto-Joint)


Model Number: 2039
UMI Performance

UMI’s on car adjustable lower control arms utilize 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!

Chrome Moly- Chrome moly version uses 1.250″ x 0.095″ 4130 Chrome Moly steel. The Chrome Moly construction adds increased strength while reducing product weight. Make your selection below.


  • Constructed of 1.250” x 0.120” DOM mild steel tubing
  • TIG welded 4140 chrome moly tube adapters
  • On car adjustable using a chrome moly, heat treated adjuster
  • Swivel Roto-Joints installed
  • Roto-Joints are greaseable and rebuildable
  • Shipped fully assembled and ready to install
  • Uses OEM hardware
  • Brilliant and durable powder coat finish

More about Roto-Joint Technology….. UMI’s Roto-Joint, short for Rotational Joint, allows 28 degrees of total rotation and unrestricted movement throughout the vehicles suspension. The Roto-Joint is designed to work like a spherical rod end while maintaining streetable qualities of a softer bushing. The Roto-Joint is designed to articulate and prevent suspension bind, and since the installed delrin race does not deflect like softer bushings, there is an improvement in traction and a significant reduction in wheel hop. The construction of the Roto-Joint features a 4140 chrome moly, hard chrome plated spherical ball which rotates in a delrin race. The 4140 chrome moly material and hard chrome plating are designed for extensive wear resistance against hard driving and accumulated miles. The spherical ball rotates in the CNC machined delrin bushing, which is contoured for the spherical ball to allow unrestricted movement as the ball rotates. Delrin is the bushing material of choice due to its high resistance against wear, great tensile strength, and ability to maintain its physical properties. The housing of the Roto-Joint features 4140 chrome moly threads, and a CNC machined bushing holder TIG welded together for the utmost in strength and durability. The UMI Roto-Joint is adjustable and 100% rebuildable. This means as the delrin race wears the adjuster ring can be tightened using the optional spanner wrench to apply tension to the ball. If the delrin race would ever wear completely it can be replaced easily.

Spanner Wrench- This spanner wrenched is used for adjusting and disassemble of Roto-Joints used in all UMI Performance products. Over time if the delrin race inside the Roto-Joint would wear the spanner wrench is used to tighten the adjusting ring applying more pressure to the delrin inside. The spanner wrench is also used to disassemble the Roto-Joint for cleaning, inspection and rebuilding.

1 review for 82-02 Fbody UMI Performance On Car Adjustable Rear Control Arms (Poly/Roto-Joint)

  1. Rated 5 out of 5
    ( 1 reviews )

    cory ullman (verified owner)

    a great improvement over stock. noticable rear end stiffening. no more wheel hop. 166k miles on my stock suspension and this is one of the best upgrades. also purchased the matching panhard bar.

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