Motorcycle Tire Tread Structure for Stability and Cornering
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Solution Overview
Problem
Motorcycle tires face a trade-off between straight-running stability and cornering performance, with high-speed running causing increased tire diameter and radius of curvature in the tread shoulder regions, impairing cornering performance.
Innovation Solution
A motorcycle tire design with a tread reinforcing structure comprising a belt layer and a band layer, where the band layer is spirally wound with a smaller developed width than the belt layer, and specific cord angles and widths are used to maintain a smaller radius of curvature in the crown region while enhancing cornering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the band layer is disposed radially outside the belt layer with a narrow width to constrict the tread crown region for straight-running stability, then straight-running stability is improved, but the radius of curvature in the shoulder region increases at high speed which impairs cornering performance
Solution Approach 1:
The patent applies local quality by creating different radius of curvature characteristics in different regions of the tread. Specifically, the crown region (center) has a smaller radius of curvature (Rc) to maintain stability, while the shoulder region has a larger radius of curvature (Rb) to enable better cornering. This is achieved through the specific configuration of the band layer with cords arranged at different angles and the resulting tread profile geometry, where Rc < 0.95×tire width and Rc < Rb, creating zone-specific mechanical properties that simultaneously satisfy both straight-running stability and cornering performance requirements
2Ease of operation
If the tire outer diameter increases in the shoulder region at high speed, then the radius of curvature increases which may improve comfort, but cornering performance is impaired
Solution Approach 1:
The patent applies preliminary action by pre-configuring the tread reinforcing layers (belt layer and band layer) with specific cord arrangements and angles before the tire is put into service. The band layer cords are arranged at angles of 0-15 degrees relative to the circumferential direction, creating a predetermined tread profile geometry with specific radius of curvature characteristics. This preliminary structural configuration ensures that when the tire operates at high speeds, the shoulder region maintains an appropriate radius of curvature (Rb > Rc) that preserves cornering performance, preventing the harmful effect of excessive diameter increase before it occurs
Data Source
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AI summary
A motorcycle tire 1 comprises a tread portion 2 provided with a belt layer 7 and a radially outer band layer 8. The belt layer 7 comprises a first belt ply 11 on a carcass 6 and a second belt ply 12 thereon. The band layer is made of a spirally wound band cord and has a developed width smaller than that of the belt layer. In a meridian cross-section of the tire mounted on a standard wheel rim at an internal pressure of 10 kPa: the radius of curvature Rc of the ground contacting surface of the tire in its crown region is less than 95% of the cross-sectional width of the tire; and the radius of curvature Rc is smaller than a radius of curvature Rb of the ground contacting surface in shoulder regions.