Originally Posted by 130R
The sway bar isn't a lever, and doesn't gain mechanical advantage by being longer, in fact, because the stiffness of a sway bar is proportional to its length, they lose stiffness, or become less efficient the longer they are.
The stiffness of a sway bar is also proportional to the 4th power of the diameter, so it's no coincidence that the FE4 rear bars have a larger diameter than the FE3 rear bars.
Sway bars do utilize lever arms at the ends, but once again, these are proportional to their length, which is why the closest hole to the bar is the stiffest setting, and the further out you go, the less efficient they are.
The FE3 bars also appear to have shorter lever arms (more efficient) than the FE4 bars.
So why do people keep posting the FE4 bars are more efficient? Is this just an assumption that bigger/longer is better? Or is there something I'm missing?
The proof is in the pudding. Try putting your finger next to hour thumb straight out vertically and press down with your other finger on your other hand in a perpendicular position then put that same finger further out towards the end of the vertical finger you will notice that the further out the finger pressing down is placed the more effective it is. Yes it is true that the longer the bar the weaker at the end but with a solid or larger diameter hollow bar placed more outboard the more effective. This would also work if we could place the rear shock a tad bit more outward like say .5" or so to still allow tire fitment. The same shock with say a 600lbs spring would be more effective if it was placed more outboard towards the hub.