Rolling resistance of tires is a highly important property for tire development as well as tire traction. The rolling resistance is mainly generated by energy loss of tire components during tire deformation, because tires transform their shape from round to flat at their contact patch. It is known that to reduce the rolling resistance, tanδ of rubber around 10 Hz should be decreased. In general, silica filled rubber shows lower tanδ around 10 Hz compared to carbon black filled rubber. On the other hand, frictional force of rubber consists of two main terms. One is hysteresis term and the other is adhesion term. It is reported that silica filled rubber shows higher frictional force in comparison with carbon black filled rubber, because of higher adhesion component of friction. Therefore, silica filled rubber can improve not only rolling resistance but also traction of tires.
X-ray and Neutron scattering results show that dispersed structure of silica agglomerates in rubber is different from that of carbon black agglomerates. It is considered that the good performance of silica filled rubber in rolling resistance and traction correlates to the silica dispersed structure in rubber.