Motorcycle Tire Set With Split Hardness for Stability and Turning
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Solution Overview
Problem
Current motorcycle tire sets face challenges in achieving high-speed stability and turning performance, especially in sports category applications for circuit driving.
Innovation Solution
A motorcycle tire set design featuring a front-wheel tire and rear-wheel tire with toroidal carcasses, jointless band plies, and distinct tread rubber hardness and angles, where the front-wheel tire's carcass cords are angled ≤65 degrees and the rear-wheel tire's crown rubber has higher hardness, enhancing steering stability and turning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the carcass cord angle of the front-wheel tire is reduced to improve steering stability, then steering stability is improved, but high-speed stability performance deteriorates
Solution Approach 1:
The patent applies different carcass cord angles to the front-wheel and rear-wheel tires. The front-wheel tire uses a smaller carcass cord angle (≤65 degrees) optimized for steering stability, while the rear-wheel tire uses a larger carcass cord angle optimized for high-speed stability. This local differentiation allows each tire to be optimized for its specific functional requirements without compromising the other.
2Ease of operation
If the crown rubber hardness of the rear-wheel tire is increased to improve turning performance, then turning performance is improved, but ride comfort deteriorates
Solution Approach 1:
The patent specifies different rubber hardness values for the crown rubber portions of the front-wheel and rear-wheel tires. The rear-wheel tire has a higher crown rubber hardness (Hc2) than the front-wheel tire (Hc1), optimizing the rear tire for turning performance while the front tire maintains lower hardness for ride comfort. This localized material property differentiation resolves the contradiction between turning performance and ride comfort.
3Weight of moving object
If jointless band plies are used to reduce weight, then weight is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent eliminates the joints between band plies by using jointless band plies where the band cords extend continuously without interruptions. This removes the joint components and their associated manufacturing complexity while achieving weight reduction. The jointless design simplifies the overall structure by taking out the joint elements that would otherwise be required.
Data Source
AI summary
A motorcycle tire set includes a front-wheel tire and a rear-wheel tire. Each of the front and rear-wheel tires includes a carcass, a band layer arranged radially outwardly of the carcass in the tread portion, and a tread rubber arranged radially outwardly of the band layer. The carcass includes a carcass ply including carcass cords. The band layer includes a jointless band ply in which a band cord is circumferentially wound spirally at an angle equal to or less than 5 degrees. The tread rubber includes a crown rubber portion. An angle θ1 of the carcass cords of the front-wheel tire is 65 degrees or more with respect to the tire circumferential direction. A rubber hardness of the crown rubber portion of the rear-wheel tire is greater than a rubber hardness of the crown rubber portion of the front-wheel tire.