MAD Helper springs are progressively wound steel coil springs fitted in conjunction with the original suspension. MAD Progressive Springs have little or no effect while the vehicle is unladen. As the load imposed on the suspension increases, the springs quickly become stiffer, reducing the amount of 'sag' improving the ride height, handling and safety of the laden or towing vehicle. Where space or the design do not permit an additional spring, a complete replacement main-spring is fitted with the same improved characteristics.