StreetGRIP rear coil springs improve the handling, ride quality and stance of your 1958-1964 GM B-Body muscle car including Bel Air, Biscayne, Impala and El Camino models. They feature a dual rate design spring which gives your classic the best of both worlds. The "soft" spring section helps your car to comfortably transition over small road irregularities. As your car's springs further compress -- such as when encountering large bumps and cornering loads -- the design transition to the firmer spring rate. StreetGRIP coil springs are CNC cold-wound from high tensile premium steel by then powder-coated for long-lasting, consistent operation. RideTech works closely with Hyperco, our technology partner, to develop B-body-specific springs to ensure the best possible performance and comfort.