Bicycle Tire Bead Structure for High-Load Rigidity

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Bicycle tires, particularly those used in electric bicycles and off-road bicycles, experience substantial torsional, longitudinal, lateral, and vertical deformations under high loads, affecting performance in acceleration, braking, handling, and safety due to insufficient rigidity.

Innovation Solution

The tire design incorporates an elastomeric material filler positioned radially outer to the bead core and axially between the carcass plies, anchored by a loop that extends around the bead core to prevent sliding and enhance rigidity, with a bead core to bead core ply providing additional support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the tyre uses conventional carcass structure without additional filler, then the device complexity is low, but the rigidity (vertical, torsional, lateral, longitudinal) is insufficient under high loads

Engineering Contradiction:
ImproverigidityVSAvoidstructure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The elastomeric material filler is nested within the tyre structure, positioned between the bead core and the carcass plies. This nested configuration allows the filler to be integrated into the existing tyre architecture without adding external components, thereby increasing rigidity while minimizing structural complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention introduces an elastomeric material filler with specific properties (different from the surrounding tyre materials) to create a composite structure. This composite approach combines the bead core, filler, and carcass plies to achieve enhanced rigidity characteristics that cannot be obtained with conventional homogeneous tyre structures

Inventive Principle:
Principle #40Composite materials

2Strength

If the elastomeric material filler is not anchored to the bead core, then the ease of manufacture is high, but the rigidity enhancement is insufficient due to sliding between filler and bead core

Engineering Contradiction:
ImproverigidityVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The anchoring mechanism is designed to be pre-integrated into the tyre structure during manufacturing. The elastomeric material filler is positioned and anchored to the bead core before the final tyre assembly is completed, ensuring proper alignment and connection without requiring complex post-assembly operations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The elastomeric material filler itself acts as a flexible anchoring element that can conform to the bead core geometry and provide secure attachment. The flexible nature of the elastomeric material allows it to be effectively anchored to the bead core while maintaining the ability to accommodate tyre deformation during use

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP4375086B1Bicycles tyre
Publication Date: 2025.10.29 PIRELLI TYRE SPA
  • EP4375086B1 patent drawingFigure 1
  • EP4375086B1 patent drawingFigure 1A
  • EP4375086B1 patent drawingFigure 2~3

AI summary

A bicycles tyre (100) comprises a pair of bead cores (8), a carcass structure (2) turned around the pair of bead cores (8) and a tread band (4) radially outer to the carcass structure (2); at each bead core (8) being provided: an elastomeric material filler (12) which extends in a radial direction for a first length (H1) starting from the bead core (8), a loop (15) interposed between the carcass structure (2) and the elastomeric material filler (12), turned around the bead core (8) so as to define a first flap (15a) axially outer to the elastomeric material filler (12) and a second flap (15b) axially inner to the elastomeric material filler (12), wherein the first flap (15a) extends in a radial direction for a second length (H2) and the second flap (15b) extends in a radial direction for a third length (H3). A bead core to bead core ply (14) is placed radially outside the carcass structure (2) and radially inside the tread band (4).