This study utilized computer simulations to analyze the influence of vehicle weight on automotive performance, terrain traversability, combat effectiveness, and operational energy for the M1A2 Abrams, M2A3 Bradley, and M1126 Stryker. The results indicate that a 15% reduction in combat vehicle weight correlates to 0-20% or greater improvements in: automotive mobility (top speed, speed on grade, dash time, fuel economy), terrain traversability (minimum required soil strength, % Go-NoGo, off road speed), combat effectiveness (% of combat effective outcomes, hits sustained, time, average and top speed in kill zone), and operational energy (gallons of fuel and fuel truck deliveries). While it has always been “understood” that vehicle weight impacts performance, this study has actually successfully quantified the impact. Through the use of multiple simulation tools, this study shows that reduced vehicle weight improves automotive performance, which directly improves the combat effectiveness in this current combat scenario. This study demonstrates that weight has a far more significant impact than previously known, and traditional methods of simply adding capability at the expense of weight could actually be self-defeating: reduced combat and operational capability of the combat platform. This paper also examines the relevance of mobility-based combat effectiveness within the framework of Brigade Combat Team fundamental operations, which provides direction and context for future studies.