Dual-Layer Tire Tread Composition for Grip and Low Rolling Resistance

The tread portion is divided into multiple tread layers with different stiffness characteristics. The radially outer tread layer has lower stiffness (G′1: 1-3 MPa) to reduce rolling resistance, while the radially inner tread layer has higher stiffness (G′2: 4-12 MPa, at least 3 MPa higher than G′1) to improve handling performance. This segmentation allows each layer to perform its specific function without compromising the other.

Different regions of the tread structure are assigned different mechanical properties. The outer tread layer contacting the road surface is designed with softer properties for low rolling resistance, while the inner tread layer is designed with stiffer properties for handling support. This local differentiation of material properties resolves the contradiction between rolling resistance and handling performance.

The tread structure is segmented into functional layers where the outer layer optimizes for low rolling resistance and the inner layer optimizes for stiffness. This allows the tread formulation to achieve low rolling resistance in the outer layer while maintaining high stiffness through the inner layer's higher G′ properties.

The multi-layer tread structure functions as a composite system where each layer contributes different properties. The combination of a softer outer layer and stiffer inner layer creates a composite structure that simultaneously achieves low rolling resistance and high handling performance, neither of which could be achieved by a single homogeneous material.