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OEM Ball Joint vs Polyurethane Bushing

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    OEM Ball Joint vs Polyurethane Bushing

    Hi all,

    I am informed that the Ball Joint does not have deflection (if that remains true).
    I understand that a Polyurethane bushing can be better than an OEM bushing, given that it deflects less, but does not completely eliminate deflection (given how hard the durometer is).

    However, If one has the choice between an OEM Ball Joint vs Poly Bushing, does not the OEM Ball Joint provide more performance, given it has no deflection?

    For reference, the diagram by Rogue Engineering below shows their RE.551 and RE.247 in the rear suspension, which replaces the OEM Ball Joints.
    If one were to use Poly Bushings here, in those places (instead of new OEM Ball Joints), would one actually decrease the performance of their suspension.



    NOTE: Rogue Engineering provides Bearings in those locations (which is not part of my question). Their diagram is just used for reference between Ball Joint and the Poly discussion.




    Thanks!

    #2
    It would probably feel stiffer and more connected at first, feeling like an upgrade. But the twisting and binding would apply forces to a poly bushing in ways it's not designed to stand up to, leading to rapid wear and deterioration of the material. I believe this is why I see most people advocating for RTABs to be replaced with bearing-type designs instead of straight poly bushings.
    '03.5 M3 SMG Coupe - Jet Black / Black

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      #3
      I like a bushing where there's not going to be any or little movement, rotation, articulation. Like the nose bushing in the shifter carrier or subframe/diff or FCABs. The problem with ball joints for me, is the lack of elasticity or bounce back. I like our steering with rubber fcabs because of the tough rubber. I went balljoint FCABs, and the steering lost that "pull back" or spring. It felt too loosey goosey. Direct in the feel of the feedback, but too easy. I want the bushing to "fight" back.

      To me, it seems like a ball joint or Heim has infinite deflection, unless it's mechanically limited in a particular direction. So ball joint RTABs are free to rotate on an axis that's acceptable, but doesn't allow gross toe changes - at least as far as I understand it.
      Last edited by Tbonem3; 04-14-2020, 10:50 AM.
      DD: /// 2011.5 Jerez/bamboo E90 M3 · DCT · Slicktop · Instagram
      /// 2004 Silvergrey M3 · Coupe · 6spd · Slicktop · zero options
      More info: https://nam3forum.com/forums/forum/m...os-supersprint

      Comment


        #4
        Originally posted by Tbonem3 View Post
        I like a bushing where there's not going to be any or little movement, rotation, articulation. Like the nose bushing in the shifter carrier or subframe/diff or FCABs. The problem with ball joints for me, is the lack of elasticity or bounce back. I like our steering with rubber fcabs because of the tough rubber. I went balljoint FCABs, and the steering lost that "pull back" or spring. It felt too loosey goosey. Direct in the feel of the feedback, but too easy. I want the bushing to "fight" back.

        To me, it seems like a ball joint or Heim has infinite deflection, unless it's mechanically limited in a particular direction. So ball joint RTABs are free to rotate on an axis that's acceptable, but doesn't allow gross toe changes - at least as far as I understand it.

        What ball joint FCAB did you use previously ?

        Comment


          #5
          TMS. Only one I know of unless Fall line's came out. Maybe Cayn CMP is making one too?
          DD: /// 2011.5 Jerez/bamboo E90 M3 · DCT · Slicktop · Instagram
          /// 2004 Silvergrey M3 · Coupe · 6spd · Slicktop · zero options
          More info: https://nam3forum.com/forums/forum/m...os-supersprint

          Comment

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