Multidisciplinary design instances arise when the performance of large-scale, complex systems can be affected through the optimal design of several smaller functional units or subsystems. In this paper, we describe the use of multidisciplinary design optimization to resolve system-level tradeoffs during racecar design. Our implementation involves three design variables: weight distribution, aerodynamic downforce distribution, and roll stiffness distribution. The objective is to determine the racecar configuration that minimizes lap time around a skidpad of constant radius while satisfying a yaw balance constraint. The force and aerodynamic components of the design optimization problem provide the multidisciplinary setting in which Collaborative Optimization is implemented and compared with previous results obtained from a traditional optimization formulation.