This article presents a new method to help achieving the rapid response of tire virtual optimization–predicting the camber-sideslip combined mechanical characteristics based on pure camber and pure sideslip. First, the influence mechanism of camber on sideslip is explored. Using the method of combining test and simulation, a finite element (FE) model of 235/55R18 tire is established, and the influence law of camber on sideslip is summarized. Secondly, the prediction method is studied. The linear region prediction is based on the load transferring along tire width caused by camber. The transition zone mechanical characteristics is predicted by treating camber as a function of load and the friction prediction considers local carcass camber (LLC) function. Finally, the application verifications of the prediction method in Magic Formula (MF) and UniTire are carried out. The prediction results are compared with the Similarity result and the MF identification result.