I have spent the last two hours reading all the threads about poly vs. rubber T/A bushings. The rubber bushings are hard mounted and the rubber twists about the sleeve axis to provide for suspension travel. The poly bushings seem to be a favorite among alot of the users except a few of the forum vendors favor the rubber (VPB). Personally, the design of the poly bushing doesnt seem to work as intended in this application.
The intended bearing surface of rotation seems to be either between the OD of the sleeve (spacer) and the ID of the poly bushing or between the OD of the poly bushing and the ID shell. But the later cant happen because you squeeze the flange of the poly bushing when tightly installed in the pocket. The first cant happen because the flared end of the inner sleeve is slightly recessed below the surface of the outer washer.
I simulate the arm installed in the pocket by putting the arm on the bench and squeeze the poly setup in the vise and move the arm up and down to simulate suspension travel. On one side, the cup spins in the arm and the other side, the poly spins in the cup along w the inner washer. On other arm, one side of the poly spins on the sleeve and the other side the poly flange rotates against the outer washer. In both arms, squeaks like crazy.
In the race car, we use heim joints all over for shocks, third link arm, lower control arms. Does anyone make a similar sperical or heim joint for this T/A bushing?
At this point, the original rubber bushing makes the best sense.
Sorry for being long winded but this is nuts.