Measurement & Calculation of Vehicle Center of Gravity Using Portable Wheel Scales

Knowledge of the vehicle Center of Gravity (CG) position is important for the calculation of vehicle performance parameters including the handling characteristics of racing vehicles and the rollover assessment of street vehicles. This paper focuses on a method to measure CG position commonly used by racing teams. This method uses scales placed under each wheel for longitudinal CG position, and for CG height, involves raising one end of the vehicle and measuring the change in scale forces.

Many of the equations in use to determine CG height using this method do not correctly account for vehicles with different front and rear wheel loaded radii; a common situation in racing vehicles. This paper presents the derivation of an equation for this case, shows the key characteristics of the method using a non-dimensional approach, and discusses the limitations and advantages of the wheel scale method.