3 wheel Bicycle design: Front Axle

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Discussion Overview

The discussion revolves around the design of a front axle system for a three-wheel cargo bicycle, focusing on the mechanics of steering and wheel alignment. Participants explore various configurations for the axle and how they affect the movement and turning of the bicycle.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes a design that links the headset to the left wheel and uses a straight rod to the right wheel, proposing a T-shaped axle configuration under the cargo box.
  • The same participant questions how to translate the turning arc into effective movement for both wheels, expressing concern that the perpendicular force may not achieve the desired turning effect.
  • Another participant suggests considering a Y-shaped design with either a central pivot point or two equal distance arms from the headset to the wheels, noting the challenge of fixed points and rod lengths that limit articulation.
  • A request for a visual representation of the design is made to aid understanding.
  • One participant mentions their own project involving a two-wheeled unicycle, indicating potential relevance to the discussion.
  • A participant shares links to external resources that may relate to the steering mechanisms being discussed, including a front wheel steering assembly and Ackermann steering geometry.

Areas of Agreement / Disagreement

Participants express differing views on the axle design, with no consensus reached on the optimal configuration or the mechanics of force translation during turning.

Contextual Notes

Participants highlight limitations related to fixed points and rod lengths, which may affect the articulation of the proposed designs.

Who May Find This Useful

Individuals interested in bicycle design, mechanics of steering systems, or those working on similar projects involving multi-wheeled vehicles may find this discussion relevant.

Senoraraton
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I'm trying to understand the angles and force involved with my current project of building a 3 wheel front loading cargo bicycle. The current design stipulations maintain that the rear wheel always remain inline with the cargo(There are a vast majority of designs that do not adhere to this). I'm trying to develop the front axle system and have seen one design that links the headset to the left wheel and then runs a straight rod to the right wheel. I would like to split the axle underneath of the cargo box, in the shape of a T.

If I have a rod to the center of the cargo box directly between the two wheels, when the headset turns it will move the rod towards one wheel, and away from the other. This creates an arc that I can adjust based upon the turning radius of the handlebars. My thoughts on this though are that if the side axles to the wheels are mounted directly centrally in the hubs, then this force of pushing/pulling is going to achieve nothing because the force is directly perpendicular to wheels? How do I translate this arc into a pushing of one wheel, and an equal force of pulling on the other wheel to ensure they remain in unison, and turn in the proper direction?
 
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So after some thought, I am considered not making a T design, but using a Y design with with either a central pivot point creating equal distance arms from the headset and wheels to a central focal point, or possibly just using two equal distance arms from the headset to the wheels without a central connection point. The underlying problem that I can't quite understand is that the points are all fixed, and the rod lengths are fixed as well, which means everything is bound up and can't articulate.
 
I'm having a hard time visualizing your design. Can you post a drawing? Even a rough sketch would be helpful.
 
This might be useful for me. I'm working on my 2 wheeled Unicycle.
 

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