This paper focuses on predicting the out-of-plane rigid ring model parameters of an off-road truck tire running over a flooded surface. The truck tire size 315/80R22.5 used in this study is modeled using Finite Element Analysis (FEA) technique and validated in static and dynamic responses. The flooded surface is modeled using Smoothed-Particle Hydrodynamics (SPH) technique and Murnaghan equation of state. The contact between the truck tire and a flooded surface is defined using node-symmetric node-to segment contact with edge treatment algorithm. The out-of-plane rigid ring tire model parameters include the lateral stiffness, cornering stiffness, self-aligning moment stiffness, and relaxation length. The out-of-plane rigid ring model parameters are computed at different operating conditions including various inflation pressures, vertical loads and water depth. The effect of the previously mentioned operating conditions on the tire-flooded surface interaction is examined and investigated.