The use of dampers (shock absorbers) in heavy truck suspensions is central to reducing dynamic wheel loads. Dynamic wheel loads are responsible for a significant component of vehicle related road damage. Improving the viscous damping characteristics of suspensions will substantially reduce dynamic wheel loads thereby enhancing suspension “road-friendliness”. Because dampers deteriorate over time, a new test is required to determine the in-service condition of dampers. There is a need to develop improved dampers that are optimized to reduce dynamic wheel loads while providing good ride quality. They must be sufficiently robust to dissipate the required energy from various magnitudes of road unevenness over extended life cycles.