Dual-Ply Motorcycle Tyre Structure for Road-Off-Road Stability
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Solution Overview
Problem
Existing motorcycle tyres for 'big enduro' motorcycles struggle to balance high-performance road stability and off-road capabilities, with current solutions either prioritizing one environment over the other, leading to compromised performance in both.
Innovation Solution
A motorcycle tyre design featuring a radial carcass structure with two juxtaposed carcass plies of low-modulus textile reinforcing cords and a tread band with a central annular sector made of a compound with high static mechanical properties and low hysteresis, combined with softer compounds in lateral sectors for improved road handling and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the tyre uses a tread pattern with high void/solid ratio for off-road traction, then off-road performance is improved, but high-speed stability on road surfaces deteriorates
Solution Approach 1:
The tyre employs different tread compounds with distinct properties in different regions: the central annular sector uses a compound optimized for road stability with lower hysteresis, while lateral annular sectors use compounds with higher hysteresis for off-road traction. This local differentiation allows the tyre to deliver context-appropriate performance across different operating conditions.
2Stability of the object's composition
If the tyre uses high-modulus textile yarns in carcass plies for structural stiffness, then high-speed stability is improved, but dry and wet handling performance deteriorates
Solution Approach 1:
The invention specifies precise parameter ranges for the textile yarns (tenacity between 0.35-1.2 cN/Tex at 2% elongation, and 0.5-3.0 cN/Tex at 5% elongation) and for the tread compound (static elastic modulus Ca3 between 9.0-14.0 at 70°C). These controlled parameter changes enable optimization of both stability and handling characteristics.
3Ease of manufacture
If the tyre uses a single compound for the entire tread band, then manufacturing simplicity is maintained, but performance adaptability across different terrains deteriorates
Solution Approach 1:
The tread band is segmented into distinct annular sectors (central and lateral regions) that can be made from different elastomeric materials or compounds. This segmentation allows each region to be optimized for its specific function while maintaining a relatively simple overall structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances high-speed stability under varying loads without compromising dry and wet handling, offering a balanced performance for both road and non-demanding off-road conditions.
Implementation Method 1
a tread band having a central annular sector made from a vulcanized elastomeric material with high static mechanical properties and low hysteresis
Implementation Method 2
lateral annular sectors with higher hysteresis
Data Source
AI summary
A motorcycle tyre, comprising a radial carcass structure (2) and a tread band (8) applied at a radially outer position with respect to the radial carcass structure (2), wherein the radial carcass structure (2) comprises a first carcass ply (3a) and a second carcass ply (3b) including a first plurality of textile reinforcing cords (30) and a second plurality of textile reinforcing cords (32), respectively, wherein the first textile reinforcing cords (31) are parallel to each other and the second textile reinforcing cords (33) are parallel to each other and have a respective first and second inclination at a crown portion (8c) of the tread band (8) with respect to an equatorial plane (X-X) of the tyre, wherein said second inclination is opposite to said first inclination. The first textile reinforcing cords (31) and the second textile reinforcing cords (33) have a tenacity comprised between 0.35 cN/Tex and 1.2 cN/Tex at 2% elongation and comprised between 0.5 cN/Tex and 3 cN/Tex at 5% elongation. At least one central annular sector (8a) of the tread band (8) arranged astride of the equatorial plane (X-X) is made of a vulcanized elastomeric material having a static elastic modulus Ca3 measured at 70° C. comprised between 9.0 and 14.0, a tandelta measured at 70° C. and 10 Hz comprised between 0.120 and 0.160, and a dynamic elastic modulus F measured at 70° C. and 10 Hz comprised between 3.7 and 4.1.