<p>This paper presents a parametric design approach for the two-member Transmotor-Flywheel electric vehicle powertrain. The vehicle's dynamic model is analyzed to derive the powertrain requirements under various driving cycles, acceleration, and gradability. A parametric design is conducted for the electric motor and flywheel components based on these derived requirements. Subsequently, a comprehensive performance comparison is performed, contrasting a conventional electric motor powertrain architecture with the Transmotor-Flywheel architecture under the same driving cycles. The evaluation focuses on key metrics such as the state of charge, driving range, and overall performance. The results demonstrate the Transmotor-Flywheel architecture's superior range extension capabilities, providing a strong foundation for future research and development in electric vehicles.</p>