Most of driving and resistant forces that enable braking, acceleration, and cornering of a vehicle are created at the tire’s contact zone with the road. Tires have complex structure and are composed of various components. The geometrical and mechanical properties of the structure affect the characteristics of the forces and torques created at the contact zone and consequently, the vehicle's behavioral specifications such as braking, acceleration, and cornering characteristics are affected. Because of requiring advanced equipment and high costs of practical tests, computer-aided simulation has received attention. In this study, the effect of some geometrical and mechanical properties of a tire's structural components on its forces and moments characteristics and subsequently, on vehicle dynamics performance is investigated. The study of the sensitivity of tire behavior to changing the geometrical and mechanical properties of its components has been carried out using finite element method with the help of Abaqus. For this purpose, at first two features of rim width and sidewall height for some tires that are 185mm wide with the constraint of outer diameter remaining constant, are being investigated. Thus, the finite element models of 8 different tires that are only distinguished in terms of rim width and sidewall height have been created and the behavior of these tires has been compared by simulations of stiffness tests and rolling-slip tests. Next, sensitivity of the behavior of one of the structures to the change of stiffness of the reinforcing fibers, the ratio of the fiber cross-sectional area to their distances, and the thickness of the rubber component is investigated. By applying these changes to both the circumferential (belt) and sidewall components, it has been possible to carry out a comprehensive and separable investigation, the result of which, is suggesting a modified tire structure and showing that the proposed structure, all tire behavioral aspects (steady-state longitudinal, steady-state lateral, transient longitudinal, and transient lateral) are superior to the original structure. To investigate the effect of tire characteristics on vehicle dynamic performance, several road tests on a full vehicle for four different tires, one of which was the same modified structure, were simulated in CarSim. In each test, at least one of the parameters associated with the discussion of vehicle dynamic performance evaluation such as brake distance, understeering gradient, steering effort, vehicle slip angle, lateral deviation from target path, etc. is measured. The vehicle model used, is one of the instant vehicle models from CarSim. It uses the same default values for all vehicle subsystems except for the tires. For tires, pacejka 5.2 tire model is used. Numerical values of the coefficients of this tire model are calculated by fitting the curves of the tire forces and moments obtained by finite element simulation of required stiffness and rolling-slip tests. Simulation results of the road tests, in addition to providing useful information about the effects of rim width and sidewall height of 185mm wide tire on vehicle behavior, have shown that the vehicle behavior is more desirable with the proposed tire structure than with the early tire structures. Keywords : Automobile, Tire Behavior, Finite Element Tire Model, CarSim, Pacejka 5.2 Tire Model