Originally Posted by OneMoreTime
If you can imagine a four bar with one of the bars replaced by the spring then you have it...
Following up a bit on Brew's comments, I'm wondering if it truly IS like a four bar. The main difference I see is the with the quarter ellipticals, two of the bars are designed to flex...probably by 1"-2" in each direction measured at the tip of the spring. In a 4-bar setup, none of the bars flex.
Won't this flexing or bending of the lower bars on the midget setup cause the attachment point to lengthen and shorten as the length of the lower bar (the spring) is lengthened and shortened during the bending action? And the axle itself is prevented from twisting or rotating to accommodate that movement by the upper rigid bar. I'm just wondering how much actual travel you could get on that front axle before it it would bind up.
The other difference I see between the midget and a 4-bar, is that with a 4-bar all four bar ends are designed to pivot so that the bars can always remain parallel. In the midget setup there is one bar end (the frame mount for the elliptical) that is rock solid. To me this would change the entire dynamic of a 4-bar system if any one "pivot" was suddenly welded solid to the frame or to the axle.
Obviously the system works, at least for this type application. But does it really follow the rules and design principles of a 4-bar setup?