A torsion bar is a type of spring used in vehicle suspension systems. It consists of a long, cylindrical metal bar that twists when a load is applied, providing resistance and support. This design allows for a compact and lightweight suspension system, making it popular in various vehicles, including some models of automobiles and military vehicles. When the vehicle encounters bumps or uneven surfaces, the torsion bar absorbs the impact by twisting, which helps maintain stability and comfort. The amount of twist determines the spring rate, allowing for adjustments in ride quality and handling. Torsion bars are often adjustable, enabling mechanics to fine-tune the suspension for specific driving conditions.