1978-1996 GM B-Body Boxed Rear Lower Control Arms- Poly/Roto-Joint
UMI’s boxed lower control arms utilize our Roto-Joint technology for a bind free performance and quiet comfortable ride quality. The boxed control arms are fabricated from 0.120” wall thickness rectangular tubing, CNC machined drawn over mandrel bushing holders and MIG welded end caps to keep out unwanted road debris. Each control arm features the correct provisions for adding a stock or aftermarket rear sway bar, sway bar holes are reinforced with a 0.120” wall thickness steel sleeve that is TIG welded and sanded into place. The solid construction combined with the delrin lined Roto-Joints eliminate control arm flex and bushing deflection for improved traction and reduced wheel hop. The installed Roto-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. The installed UMI Roto-Joint allows rear end free movement when high handling, auto cross or road race is a concern while still being a 100% streetable setup. The installed delrin race, which lines the spherical ball, absorbs shock and road noise for a quiet and smooth operation on any street or track driven vehicle. This control arm set features polyurethane bushings on one end and UMI’s swivel 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!
- Constructed of 3” x 1-1/2” x 1/8” rectangular steel tubing
- MIG and TIG welded construction for superior strength
- CNC machined for accurate tolerances and perfect fit
- Spherical Roto-Joints installed
- Energy Suspension greaseable polyurethane bushings
- Reinforced sway bar holes
- 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 wrench is used for adjusting and disassembling 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.