Vehicles-in-Use Sub-Limit Maneuvers. Volume III: Effects of Vehicle-in-Use Spring Sag on Vehicle Handling and Braking

摘要

The report presents results of an investigation into the influence of sagged coil springs and coil spring spacers on handling performance of two full-sized automobiles. The findings relate vehicle stability factor (a measure of the basic understeer intentionally designed into the vehicle steering and handling characteristics) and controllability with change in ride height, sprung mass roll axis, and suspension bump-stop bottoming. Results show consistent and measurable differences in handling parameters, depending upon location of sagged spring and use of spring spacers. The least desirable situation is asymmetric (i.e., one side only) sagged spring and spacer usage which produces different handling response in left versus right maneuvers and can lead to vehicle controllability problems.