Abstract: A motorcycle swingarm is shown in which each arm is an extrusion of lightweight metal which in cross-section is a diamond with a cross rib and integral upper and lower fins. The upper fin is the larger, and is shaped to taper from both ends. The arms are bent slightly intermediate their ends, and at one end have a sleeve bearing welded thereto. At such one end, arcuate plates are also located between the arms and welded to them. At their other ends, each arm is slotted to receive an oblong slotted block which is welded to the arm. Also, the arms intermediate their ends have tabs welded thereto for providing connection points for shock absorbers and chain tensioners.