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Suspension bushing question

Discussion in 'Technical Q&A' started by Artvonne, Feb 28, 2005.

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  1. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
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    Paul
    #1 Artvonne, Feb 28, 2005
    Okay, I been thinking about this a while. Everyone is putting these hard bushings in thier cars, But as I havnt any experience I have a question or three.
    The OEM bushing isnt really a bushing, as much as its a flexible rubber mount that flexes as the control arms swing, and as the pivot bolt should be tightened with the car sitting normal, the rubber helps to "spring" the car back to its proper attitude. No moving parts, just the rubber being twisted this way or that.
    Either the poly is a bushing with the poly is rotating around the stationary bolt. Or, the poly is stationary with the tightened the bolt, and the control arm is the bushing, rotating around the poly bushing. Moving parts wear on things, so either the outer sleeve is being worn by the poly, or the through bolt is being worn by the poly, but either way there is wear. To what extent I have no knowledge.
    So my question then is this: Are the poly bushings levels above the OEM in better handling, or does the car just "feel" different? Would the OEM type last a lot longer? Any thoughts?
     
  2. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
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    #2 Birdman, Mar 1, 2005
    I can't tell the difference in ride. The car goes over bumps, the suspension goes up and down. Seems the same to me.

    You are right about the way the stock rubber bushings work. The part that moves is the rubber. You torque them down with the car on the ground. If you were to take the wheel and shock off, the A arms will still stick out, not droop too much, because the tension in the rubber.

    The poly ones are different. Best I can tell by looking at them all bolted in, the poly stays in place and the outer part of the bushing rotates against the poly. You can torque them with the suspension hanging because the bushing can turn freely.

    I'll bet that if they were driven hard every day, they would not last as long as the OEM ones. But under less frequent driving conditions, I'll bet the rubber breaks down faster on the OEM ones than the poly would wear out on the poly ones. Who knows. Either way, they are going to last at least 10-15 years. The poly ones are much cheaper and at least as good. Many people say they handle better, but I can't tell the difference. I just putt around trying not to get busted for speeding!

    Birdman
     
  3. Artvonne

    Artvonne F1 Veteran

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    #3 Artvonne, Mar 1, 2005
    I guess what I would be interested in, is what wears faster, the poly, or the steel bushing or bolt. Just like a steel cam in an aluminum head, if steel particles embed in the aluminum, they will cut up the cam in hours and do terrific damage. Poly can do the same thing once the steel starts sloughing off particles into the softer poly. Be a shame to ruin a control arm or wear through the bolt. I would just be interested in knowing which part is rotating inside which part. If its around the bolt, well, bolts are cheap. I am considering using rubber OEM unless I can find good results as far as durability. I figure my rubber is as old as my car, 27 years, as they are looking cracked. But they are still working and I see no hemoraging of rubber anywhere. I wouldnt expect the poly to last as long without becoming sloppy loose, but if the car handled remarkable better with them it would be worth the tradeoff.
     
  4. jmillard308

    jmillard308 F1 Veteran
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    #4 jmillard308, Mar 2, 2005
    Paul

    I considered the same issues when I replaced my bushes recently and came to the conclusion that original rubber bushings were good for me. FWIW :)

    John
     
  5. Birdman

    Birdman F1 Veteran

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    #5 Birdman, Mar 2, 2005
    Honestly, I think the only reason anyone considers the poly bushings is the fact that they are much cheaper than the OEM ones. Now that we know the guts of a poly bushing can be transplanted into an OEM shell, making replacement much easier, that's just another reason to use the poly bushings.

    As for ruining the A arm, it won't happen. Even if the poly somehow eventually wore out the outer bushing from rotating against it, that is part of the bushing, not the arm. You can grind the weld out, press it out and replace it. If you replace with OEM bushings, you have to do that anyway.

    Birdman
     
  6. Mike C

    Mike C F1 Veteran
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    Aug 3, 2002
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    Mike Charness
    #6 Mike C, Mar 2, 2005
    It's not in the up-and-down over bumps where you're supposed to notice the difference with poly... it's when you're torqueing around curves and applying more potential distortion to them.
     

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