Bicycle Head Tube Assembly Open Steerer Cable Routing

Solution Overview

Problem

Existing bicycle designs face challenges in reducing aerodynamic drag due to cable routing, particularly at the head tube and steerer tube assembly, where internal routing can limit motion and damage cables as the fork assembly rotates.

Innovation Solution

A head tube assembly with an open steerer configuration that includes external steerer tubes and guide tubes within the internal chamber of the head tube, allowing cables to route externally through the top and down tubes, eliminating interference with the steering mechanism and enabling smooth rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If cables are routed internally through the steerer tube via a hole in the steerer tube, then cable aerodynamic drag is reduced, but the steerer tube rotation is limited and cables can be damaged by the hole during over rotation

Engineering Contradiction:
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent removes the hole from the steerer tube and extracts the cable routing function from the rotating steerer tube. Cables are now routed through the stationary head tube shell and frame, separating the cable path from the rotating steerer tube. This eliminates the hole in the steerer tube that caused cable damage during rotation, while maintaining internal cable routing for aerodynamic benefits.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent divides the cable routing system into two separate functional zones: the rotating steerer tube interior (for cable storage and guidance) and the stationary head tube shell/frame (for actual cable passage). The steerer tube interior provides a guide path, while the head tube shell contains the routing aperture, separating the rotational movement from the cable penetration point.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If cables are routed internally through the steerer tube, then aerodynamic drag is reduced, but the steerer tube rotation and fork assembly movement are limited

Engineering Contradiction:
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent extracts the cable penetration aperture from the rotating steerer tube and relocates it to the stationary head tube shell. This separation allows the steerer tube to rotate freely within the head tube without cable interference, while cables still pass through the head tube shell for aerodynamic routing.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces the head tube shell as an intermediary structure that mediates between the rotating steerer tube and the external environment. The head tube shell provides a stationary routing path for cables, allowing the steerer tube to rotate independently without cable constraints, while maintaining internal cable routing for aerodynamic efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If a hole is provided in the steerer tube for cable routing, then cables can be routed internally, but the hole can damage cables during over rotation of the fork assembly

Engineering Contradiction:
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent removes the hole from the steerer tube entirely and relocates the cable routing aperture to the head tube shell. This eliminates the source of cable damage (the hole in the rotating steerer tube) while preserving internal cable routing capabilities through the stationary head tube structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of routing cables through the rotating steerer tube, the patent inverts the approach by routing cables through the stationary head tube shell. The steerer tube interior serves only as a guide passage, while the actual cable penetration occurs in the non-rotating head tube shell, preventing cable damage during rotation.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2543578B1Head tube assembly for a bicycle with cable access routing in an open steerer configuration
Publication Date: 2016.04.27
  • EP2543578B1 patent drawingFigure 1

AI summary

A head tube assembly suitable for a bicycle and comprising an open steerer configuration and cable routing. The head tube assembly comprises a head tube (121) configured to connect with the top tube (102) and down tube (104) of the bicycle. The head tube (121) includes a lower bearing component (122) and an upper bearing component (124) configured to rotatably engage the fork assembly (110). The fork assembly (110) comprises an external steerer configured to rotate externally to the head tube (121). The head tube assembly includes an upper steerer section (108) configured to secure the external steerer, and an internal chamber (130) configured with an aperture (132) for receiving one or more cables and being coupled to the top tube (102) or the down tube (104). The internal chamber (130) includes one or more guide tubes (210) configured to route the cable(s) through the interior portion of the top tube (102) or the down tube (104).