A Solid Rear Axle (SRA), also called a live axle or stick axle, is a rear suspension design where both rear wheels are connected by a single rigid axle housing containing the differential. SRA is mechanically simpler, lighter on cost, and superior for straight-line acceleration and drag racing applications. The trade-off is heavier unsprung weight and inferior single-wheel bump compliance compared to IRS. Most Mustangs from 1979-2014 use a solid rear axle. Griggs Racing’s TorqueArm, Watts Link, and Panhard Bar systems are engineered specifically for SRA platforms.