An analysis was made of the Garfield Thomas Water Tunnels four-component balance to determine why it exhibited some characteristics that were not anticipated when it was designed. The analysis involved the calculation of the effect of cross-wise forces on tension members which are the measuring elements in the balance. These cross-wise forces cause deflections in the measuring element and are called interactions. The analysis of the force cube cube-shaped balance elements involved the calculation of the deflections resulting from a force field which is completely described by three forces and three moments. The effect of these deflections on the tension member in the force cube constitutes the evaluation of interactions. The results showed the modified force cube to be significantly better from an interaction standpoint.