Angled Bicycle Frame Strut for Vertical Compliance

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Solution Overview

Problem

Conventional bicycle frames often prioritize vertical stiffness over comfort, leading to reduced ride comfort and potential discomfort for the rider.

Innovation Solution

A bicycle frame design that incorporates a strut member extending forward from the lower end of the seat tube to the down tube, eliminating the portion of the seat tube below the bottom bracket, and adjusting angles and lengths of frame components to reduce vertical stiffness while maintaining horizontal stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional bicycle frames prioritize vertical stiffness, then structural strength is improved, but ride comfort deteriorates

Engineering Contradiction:

Improvevertical stiffnessVSAvoidride comfort

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The seat tube is segmented into two portions: an upper portion that maintains structural integrity and a lower portion that is eliminated. The strut member connects to the down tube instead of extending to the bottom bracket, creating a segmented structure that allows vertical compliance while maintaining horizontal stiffness for proper force transfer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The angle of the strut member is specifically configured to be between 30-60 degrees relative to the horizontal plane, and the strut connects to a specific location on the down tube. These parameter changes optimize the balance between vertical deflection capability and horizontal force transfer efficiency.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the seat tube extends to the bottom bracket, then structural support is improved, but vertical compliance deteriorates

Engineering Contradiction:

Improvestructural supportVSAvoidvertical deflection

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The lower portion of the seat tube below the bottom bracket is completely removed. The strut member takes over the structural support function by connecting the upper seat tube to the down tube, eliminating the need for the lower seat tube portion while maintaining structural integrity.

Inventive Principle:

Principle #2Taking out (Extraction)

3Force

If frame components are configured for maximum strength, then force transfer is improved, but ride comfort deteriorates

Engineering Contradiction:

Improveforce transferVSAvoidride comfort

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

Different portions of the frame structure have different stiffness characteristics. The upper frame structure (head tube, top tube, upper seat tube) maintains high stiffness for force transfer, while the lower structure (strut member configuration) provides vertical compliance. This local differentiation of structural properties allows simultaneous optimization of force transfer and ride comfort.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12606266B2Bicycle frame with angled strut

Publication Date: 2026.04.21 SPECIALIZED BICYCLE COMPONENTS INC

AI summary

A bicycle includes a front wheel and a rear wheel and a frameset supported on the front wheel and the rear wheel. The frameset includes a main frame and a front fork rotationally coupled to the main frame. The main frame includes a top tube, a head tube rotationally supporting the front fork, a down tube coupling the head tube to a bottom bracket, a seat tube extending downward from the top tube and including a lower end spaced from the bottom bracket, a seatstay extending rearward from the lower end of the seat tube, and a strut member extending forward from the lower end of the seat tube and connecting the seat tube to the down tube.