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?