This is an interesting discussion. I believe the pivot is the inner shaft but the stock bushing is obviously designed to cede rotationally to a degree. If this is erroneous, when pushed too hard they do rotate and break because mine did. I mentioned poly bushings to my "race specialist" and he wrinkled his face. He told me to stay stock or go with spherical bearings. He believes Poly is better, costs more and tears at the same rate as stock rubber. So if your tearing the stock stuff replacing it with expensive poly is not the best solution. He did mention how unbearable the spherical bearings are for day to day. I guess thats why we all ride on rubber. Not to mention why I replaced the torn bushings with new rubber ones. I still don't know what I'll do the next time they are shot.

Les