The ability to accurately simulate vehicle dynamics behavior with a mathematical model is limited by the quality of the tire model. In fact, the tire is often the single most important component in determining correlation between a mathematical vehicle model and measured experimental results. Tire data for heavy trucks are more difficult and expensive to acquire than passenger car and light truck data, and, consequently, there has been little published experience testing or modeling these tires. This paper shows how the analysts can integrate heterogenous tire modeling methods into one coherent tire model suitable for the simulation of an over-the-road 18-wheel tractor-trailer configuration. The methods used in this paper are: Tire F&M modeling that represents the effect of tread wear, water depth, and speed, as well as combined longitudinal and lateral slip conditions. Simulated closed loop maneuvers utilizing a path follower to ensure that variations in tire F&M properties do not influence the trajectory of the tractor's tracking reference point. The BNPS tire model is used to represent pure longitudinal and lateral data. The COMBINATOR is used to predict the combined driving/braking performance of the tire from pure longitudinal and lateral tests. Linear regression of test results are used to create a parametric representation of cornering force to include the effects of water depth, speed, and tread wear. Predicted results based on data generated by the SAE Cooperative Research Truck Tire Characteristics Programs  are compared. The tire modeling methods are brought together into one coherent Tire Model File by using the Plug ‘n’ Play Tire Interface software. The vehicle is modeled using TruckSim™. Finally, the vehicle/tire system is run through a typical constant radius understeer test for a range of tire parameters and the results are discussed.