Thanks for the un-biased post Rub...

The reason cars use soft bushings in a lot of places is for ride compliance, pure and simple. Ironically if you are going to use a part that is kind of stiff and bind prone, the UCA is the best place to do it. Because it's located on the center of the axle it doesn't see the range of motion the LCA's do.

In general that's the place I'm most likely to recommend a normal urethane bushing because it's just not flexed as much as lowers.

 

Oh, I'll give my unbiased opinions on things I have first hand knowledge with and I've been through the entire parts rack of rear control arms .

Spohn actually advertises on their website that they WILL NEVER market a solid poly upper CA because of the inherent bind issues in the upper CA. They do however sell poly lower control arms. So yeah I would agree that the upper is where most of the bind probably occurs.

Well I guess I misread your post Sam. According to Spohn most of the bind occurs in the upper CA and I've heard that before. But it does make sense that the lowers would be taking more of a load during cornering...hmmm.