SuperPro TRC6640 Fixed Offset Upper Control Arms Boost alignment and durability with SuperPro TRC6640 fixed offset upper control arms for 2–4 inch lifted 4x4s, featuring heavy-duty high-articulation ball joints and SuperPro polyurethane bushings. Features and Benefits Enhances wheel alignment on lifted 4x4 vehicles to help reduce tire wear and improve overall performance. Constructed from high-strength steel forgings and tube steel, with robot-welded components for consistent, heavy-duty reliability. Heavy-duty, high-articulation ball joint increases suspension travel without binding for improved control over rough terrain. Includes SuperPro polyurethane bushings offering superior resilience and durability compared to traditional rubber. Polyurethane is resistant to abrasion, wear, and chemicals—ideal for harsh off-road environments. Designed to add clearance, articulation, and a stronger control arm for demanding off-road conditions. TRC6640 is suited for vehicles lifted 2 to 4 inches.