Bicycle Tire Two-Ply Casing Sidewall Stiffness

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Solution Overview

Problem

Modern bicycle tires lack sufficient sidewall stiffness, which affects steering impulse and control, particularly when transferring lateral forces between the bike and the ground, and do not effectively combine the advantages of MTB and ATB tires in terms of width and reinforcement.

Innovation Solution

The tire features a unique casing construction with two unidirectional casing layers oriented at +45 and -45 degrees, along with sidewall reinforcements made of rubber strips, to enhance sidewall stiffness and provide improved lateral stiffness and flexible tread area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional bicycle tire casing construction is used, then the tire structure is simple, but the sidewall stiffness is insufficient affecting steering impulse and control

Engineering Contradiction:
Improvesidewall stiffnessVSAvoidcasing construction complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining two unidirectional casing layers with orthogonal orientations (0° and 90° to the tire centerline) to create a carcass structure that achieves superior sidewall stiffness and strength. This composite layering approach allows the tire to attain the required mechanical properties without adding excessive complexity to the overall construction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements local quality by varying the casing layer configuration in different regions of the tire. The sidewall regions utilize the full two-layer orthogonal construction for maximum stiffness, while the crown region incorporates only the necessary layers for tread support. This localized optimization provides enhanced sidewall stiffness where needed while maintaining flexibility in other areas.

Inventive Principle:
Principle #3Local quality

2Area of moving object

If wider tire design is used to combine MTB and ATB advantages, then the tire width increases, but the sidewall reinforcement becomes insufficient

Engineering Contradiction:
Improvetire widthVSAvoidsidewall reinforcement
Core Design Contradiction:
Area of moving objectVSStrength

Solution Approach 1:

The orthogonal composite casing construction (0° and 90° layers) provides exceptional sidewall reinforcement that maintains structural integrity even as tire width increases. This composite approach allows the tire to achieve wider dimensions while preserving adequate sidewall strength, effectively combining the benefits of wide ATB tires with the structural reliability of reinforced MTB designs.

Inventive Principle:
Principle #40Composite materials

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 solution results in a tire with stiff sidewalls for enhanced steering impulse and control, and a flexible tread area for better ground contact and adaptation to small undulations, effectively addressing the limitations of existing tire designs.

Implementation Method 1

an inner side of the tire carcass facing the tire interior has a fabric layer is covered, which consists of monofilament threads, which are embedded in an elastic material or in which the spaces are filled with elastic material

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3575109B1Bicycle tire with two-ply carcass
Publication Date: 2021.05.12 SPECIALIZED BICYCLE COMPONENTS INC
  • EP3575109B1 patent drawingFigure 1
  • EP3575109B1 patent drawingFigure 2
  • EP3575109B1 patent drawingFigure 3

AI summary

A vehicle tire comprises first and second bead cores (24) spaced apart from each other, a first casing layer (30) wrapped around the bead cores, a second casing layer (40) wrapped around the bead cores, and a tread layer (50). The first casing layer (30) has first edge sections (36) that overlap with each other at a zenith (Z) of the tire and terminate at first edges (39) on opposing sides of the zenith. The second casing layer (40) has second edge sections (44) that do not overlap with each other and that terminate at second edges (46) that are each substantially aligned with one of the first edges (39). The first and second casing layers (30, 40) are each made of a single unidirectional ply that are in different directions to each other. The sidewall regions and the zenith comprise four plies of casing layers throughout the tire. The tire can further include first and second sidewall reinforcements (52), which are for example rubber strips, positioned in the first and second sidewall regions.