<p>Transient tractive rolling contact behavior of tires is critical for achieving high-precision motion control of wheels, especially for high-bandwidth in-wheel motor drive systems. When it comes to real-time simulation and motion control applications, a transient tire model with a simple form and good expression accuracy is essential. The paper aims to investigate the basic characteristics and influencing factors of transient tractive rolling contact behavior of tires, and to analytically point out the way to consider the effect of wheel inertia in simplified model. A wheel dynamics simulation model is established based on the discrete brush model, incorporating wheel inertia effect. Transient tractive rolling contact behavior of tires is investigated. The effect of model simplification on the expression accuracy and the improvement method is analytically illustrated.</p>