The cause of the standing wave in radial passenger car tires is investigated using the dynamic transient finite element analysis to predict a steady free-rolling state under high-speed conditions. First, the approach is validated by high-speed durability test results on two different tires. The critical speed of the standing wave and the position of the wave according to speed are qualitatively compared with the corresponding test. In addition, the high-speed performance ranking according to the design change of the cap ply reinforcement is compared with the predicted results. As a result, the proposed model captures the test results well. Subsequently, with the help of the proposed model, the generation mechanism of standing waves is interpreted using numerical results. The phenomenon arises from the incompressible properties of rubber and the structural properties of tires. Increasing the speed gradually increases the Poisson effect while lowering the pneumatic effect. If the Poisson effect is not suppressed by the pneumatic effect, a standing wave occurs. It also reveals that cap ply design changes affect the pneumatic effect as well as high-speed performance rankings.