Someone one the Dry Dock reposted something from a Porsche list that talked about the friction of poly bushings, and how that contributed to a rough ride when poly bushings are used. For contrast, they said that rubber bushings had NO friction. While I think it's probably true that there's no sliding or starting friction in a rubber bushing, there certainly IS some resistance to turning in a rubber bushing. In a poly bushing, there's some "sticktion" as you START to move the suspension, but it smooths right out once you get past that initial resistance. Ehrenberg said something like 20#/in spring rate in a rubber LCA bushing, which is a lot. Significantly more than the typical step between t-bar sizes, in fact. If your poly bushings are lubed right, you've effectively reduced your spring rate by a size...

Now, on a drag car, I can see how you might achieve the same thing by tightening your suspension bushings with no load on the suspension, so they're pre-loaded when you set the car down. We all know that this kills bushings ASAP, though. A greased poly (or delrin, nylon, teflon, del-a-lum, etc) bushing would work nearly as well as a roller bearing, and a lot better than a rubber bushing, especially in the moments immediately after the front end started to rise. For steady-state cruising, rubber bushings are probably the way to fly. This from a guy with no rubber on the car that isn't holding glass in place...

Clair