In this paper the robust design method was applied to a vehicle wheel trim cap. A robust wheelcap design which does not fall off during operation, yet is easy to install and remove is generally desired. A generic model of the cap was first developed which relates performance measures such as insertion and removal forces to the design parameters. The model was then linked to an optimization program to solve for an optimal design. The optimized wheelcap is shown to be able to achieve the design goals despite of the high variation of the dimensions and material properties of the plastic material. The performance variation is significantly reduced when compared to the original wheelcap.