UMI Performance 4044-B Tubular Rear Upper Control Arms with Roto-Joint, Black

Engineered as a direct bolt-on replacement for factory stamped steel arms, these control arms are designed to minimize wheel hop, sharpen cornering response, and improve overall suspension consistency — on the street or at the track.

At the heart of this upgrade is UMI's proprietary Roto-Joint technology. The Roto-Joint uses a 4140 chromoly, hard chrome-plated spherical ball rotating inside a CNC-machined Delrin race to deliver 28 degrees of total unrestricted movement — providing fully bind-free suspension articulation. Unlike factory rubber or aftermarket polyurethane bushings, the Roto-Joint does not deflect under load, which translates directly into better traction and reduced wheel hop. The Delrin race is greaseable and low-maintenance, making this setup equally at home on a weekend cruiser or an autocross/road race build.

The Roto-Joint is also fully rebuildable and adjustable — as the Delrin race wears over time, the adjuster ring can be tightened to restore proper preload. If the race ever wears completely, it can be replaced individually without replacing the entire joint.

Key Features:

• Constructed of 1.500" x 0.120" DOM mild steel tubing for maximum strength and rigidity
• Mounting plate CNC machined from 0.250" thick mild steel for precision fitment
• Spherical Roto-Joints pre-installed — shipped fully assembled and ready to install
• 4140 chromoly hard chrome-plated spherical ball for exceptional wear resistance
• Greaseable Delrin race with 28 degrees of total unrestricted movement
• CNC machined for precision tolerances and accuracy
• Uses OEM hardware — no special tools required
• Durable black powder coat finish
• Installs in approximately 1–2 hours using basic hand tools

These upper control arms deliver a significant performance improvement over worn or deflection-prone factory arms, while remaining a 100% streetable solution. The combination of rigid tubular construction, precision CNC machining, and Roto-Joint technology makes the 4044-B one of the most capable non-adjustable upper control arm options available for classic GM A-Body applications.