Tyre Tread Layout Balancing Wet Drainage and Track Rigidity
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Solution Overview
Problem
High or ultra high performance car tires intended for both road and track usage face conflicting requirements of maintaining high performance, traction, and safety on varying road conditions, particularly in wet conditions, due to the trade-off between groove depth for water drainage and tread rigidity.
Innovation Solution
A tire design featuring a tread band with a central region and wide shoulder regions, including transverse grooves and annular portions with minimal void-to-rubber ratio, optimizing stiffness and drainage while maintaining performance and safety on both dry and wet surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wide and deep grooves are increased in circumferential and transverse direction to improve water drainage, then draining and grip features on wet grounds are improved, but the rigidity of the tread band is reduced leading to performance decay at high speed on dry grounds and increased noise
Solution Approach 1:
The tread band is segmented into distinct zones: a central region with limited extension (≤35% of effective width) containing circumferential ribs with transverse grooves for water evacuation, and wide shoulder regions (≥30% of effective width) with transverse grooves for lateral stability. This segmentation allows each zone to be optimized for its specific function while maintaining overall tread rigidity through the annular portions.
Solution Approach 2:
Different regions of the tread band are assigned different groove configurations and void-to-rubber ratios tailored to their specific functions. The central region features circumferential ribs with transverse grooves optimized for water drainage, while the shoulder regions have transverse grooves optimized for lateral stability. Annular portions with zero void-to-rubber ratio are strategically placed to maintain rigidity where needed, creating local quality variations that resolve the contradiction between drainage and rigidity.
2Strength
If the central region width is limited to ≤35% of effective tread band width to improve stiffness uniformity, then traction/braking performance and road holding when cornering are improved, but the area available for water drainage in the central region is reduced
Solution Approach 1:
The central region is further segmented into circumferential ribs separated by circumferential grooves, with each rib containing transverse grooves. This multi-level segmentation maximizes water drainage surface area within the constrained central region width, allowing effective water evacuation while maintaining the limited central region dimension for stiffness uniformity.
Solution Approach 2:
Water drainage capacity is enhanced by adding transverse grooves that extend in the lateral dimension across the circumferential ribs, rather than relying solely on increasing the central region width in the circumferential dimension. This dimensional approach allows adequate drainage capacity within the constrained central region width.
3Ease of operation
If annular portions with zero void-to-rubber ratio are placed adjacent to circumferential grooves in shoulder regions and on circumferential ribs, then stiffness distribution is optimized for handling and aquaplaning features, but the overall void-to-rubber ratio of the tread band is reduced
Solution Approach 1:
Annular portions with zero void-to-rubber ratio are strategically positioned in specific locations (adjacent to circumferential grooves in shoulder regions and on circumferential ribs) where maximum stiffness is needed for handling and aquaplaning resistance. This localized application of zero-void portions optimizes performance in critical areas while minimizing the overall impact on the tread band's total void-to-rubber ratio, as these portions are confined to specific annular zones rather than distributed throughout the entire tread.
Data Source
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AI summary
A car tyre (1), in particular a high or ultra high performance car tyre also suitable for use on track, is described. The tread band (8) of the tyre has a central region (L1) having a limited extension, separated from two large shoulder regions, respectively an outer shoulder region (L2) and inner shoulder region (L3). At least the outer shoulder region (L2) and the central region (L1) have a set, limited in type, number, size and extension, of transverse grooves. In the tread band (8) there are also annular portions (S 1, S2, M) substantially lacking grooves.