A Magneto-Rheological (MR) Fluid Semiactive Suspension System was tested on a Stryker vehicle, Infantry Carrier Variant (ICV), to determine the performance improvements compared to a standard ICV Stryker vehicle. In January 2005, the testing was conducted at the U.S. Army Yuma Proving Grounds located in Yuma, Arizona. The testing was conducted under the guidance of the U.S. Army Tank-Automotive Research, Development, and Engineering Center (TARDEC) of Warren, Michigan and MillenWorks of Tustin, California. The core of the system tested is comprised of 8 dampers and controllers using proprietary algorithms to modulate individual wheel forces in response to terrain inputs and body motion. Functionality of the Standard Stryker vehicle’s pressurized gas spring and ride height management system was fully retained while maintaining the physical envelope of the original damper. The systems low power consumption (80 watts idle, estimated 250 watts cross-country, and 800 watts theoretical peak) did not require an additional power source. The MR Suspension system was intentionally designed to maintain the standard wheel travel, spring rate, and spring gas volume. Over a range of off-road bump courses, the MR Stryker’s best performance was a 72% increase in the vehicle’s speed, from 22 mph (standard vehicle) to 38 mph at the 6-watt level of driver absorbed power (a measure of transmitted vibration). The system also showed marked improvements during aggressive on-road maneuvers like lane changes. The rate of vehicle roll was reduced by 30%. The maximum lane change speed increased from 38 mph (standard vehicle) to over 50 mph with the MR system. This suspension technology is a cost effective, bolt-on system that has increased cross-country speeds, improved ride quality, and helped with platform stability thereby increasing battlefield effectiveness, safety levels for the operator and crew, and reducing potential for vehicle damage and associated maintenance activities. Its relatively simple design and cost effectiveness allows insertion of this technology into new vehicle designs, both wheel and track, as well as the potential for spiral upgrades with existing vehicles.