Lower Trailing Arms - 79-04 Ford Mustang

The QA1 Lower Trailing Arms for 79-04 Ford Mustang (part number 5221) deliver precision rear suspension geometry tuning for Mustang enthusiasts pursuing handling improvements on street, track, or autocross duty. This pair of lower trailing arms features rectangular tubing construction with greasable polyurethane bushings, allowing controlled compliance without the harshness of solid mounts while maintaining predictable suspension articulation across varied driving conditions.

Steel construction finished in durable black powder coat resists corrosion and oxidation during long-term storage or outdoor use. The greasable bushing design permits periodic maintenance to extend component life and preserve suspension feel—a critical advantage over sealed or non-serviceable alternatives. At 19.61 lbs per pair, these arms maintain structural integrity without excessive weight penalty. Polyurethane material selection offers a middle ground between rubber compliance (which hardens with age and temperature cycling) and aluminum or titanium (which sacrifice compliance entirely), making it the preferred choice for chassis builders seeking balanced handling without chassis noise transmission.

These trailing arms address the specific geometry of first-generation (1979-1993) and new-edge (1994-2004) Mustang platforms, where factory rear suspension geometry can limit corner entry response and mid-corner stability during aggressive driving. Buyers upgrading their Mustang suspension for weekend track sessions, autocross competition, or street driving focused on handling responsiveness will find this QA1 component essential to a comprehensive rear suspension modernization. The rectangular tubing profile optimizes stiffness-to-weight ratio while maintaining cost-effectiveness compared to exotic materials.