Reducing the curb weight of wheeled vehicles has long been one of the priority areas of work of automotive engineers, since this can significantly improve the operational properties of a wheeled vehicle: improve dynamics, passability, reduce fuel consumption and emissions of harmful sub-stances. A significant proportion of the vehicle's curb weight belongs to highly loaded parts of the frame, transmission and suspension. Therefore, the creation of lightweight, highly loaded parts will make a significant contribution to reducing the curb weight of the whole vehicle. The paper describes the application of the topological optimization method based on finite ele-ment modeling in the design of highly loaded parts of the chassis of vehicle. An example of the syn-thesis of the power circuit of the rear suspension balance bar of an all-terrain vehicle with a descrip-tion of the design model, load modes and interpretation of the results is shown. The optimization problem was solved using a finite element model of varying density. Minimization of the potential energy of deformation was used as an objective function, and the target volume in fractions of the original design space was used as a limitation. A comparative analysis of the obtained design with analogous designs is presented. The formulation and results of an experimental study of the stress-strain state of the optimized balance bar are described. As a result of optimization, it was possible to achieve a reduction in the weight of the balance bar to 49% in comparison with an analogue design while maintaining the required strength. Experi-mental verification of the bearing capacity of the balance bar showed the need for more thorough verification calculations of optimized parts, including taking into account manufacturing and as-sembly errors.