Herb Adams front spring eye brackets

Discussion in 'Suspension, Steering, Brake & Wheel Topics' started by roadrace2, Dec 18, 2017.

  1. Skip Fix

    Skip Fix Veteran Member

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    Mar 21, 2007
    Katy,Texas
    One thing also to remember with this mod is it changes your pinion angle slightly and that affects hook also.
     
  2. G72Zed

    G72Zed Veteran Member

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    Sep 8, 2015
    Canada
    YES, without a question, After most HPDE sessions , I have found many people looking under the rear of my car, looking/asking what I use for lateral location devices such as panhard bar or Watts setup, most all the comments where "no way a leaf car should do that on a road course" & "why do you use leaf springs ??". The replies and conversations sometimes get quite colourful.

    Bought Herb Adams book decades ago, that, and the fact hquackenboss actually posting/sharing on here is absolutely awesome.

    hquackenboss, thank you for posting!!
     
  3. masck1

    masck1 Veteran Member

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    Mar 25, 2006
    Jacksonville Fl
    How do you install the brg's in the front spring eye
     
  4. hquackenboss

    hquackenboss New Member

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    Jan 13, 2015
    San Francisco, CA
    @masck1,

    Any of the kits will have instructions, but the way we used to do it is to use two machined pieces of steel tube, where the OD is a tight fit with the ID of the spring eye, where the sleeves have a step to a smaller diameter to hold the bearing from moving sideways. To keep the outer sleeve in place, weld the sleeve to the spring eye. A couple of 3/4" long welds on each side should be plenty to hold them in place. If you use good bearings, they will probably last the life of the car (I personally would not use teflon or other plastic-lined bearings for this application, but don't have a strong opinion). If you ever need to change them, a grinder will easily cut through the welds.

    @G727ed, thanks for the encouragement. Wading off topic, one comment about spring rates and wheel rates. Obviously the ARBs and front springs have to be matched to to the rear wheel rates. Also, I assume most know, the front springs will be a bunch stiffer because they work the lever of the control arms, which result in 1" inch of spring compression to equal (depending on what vehicle) typically 2 to 3" of wheel travel. Search for: wheel rate spring rate motion ratio to learn more.
     
  5. Skip Fix

    Skip Fix Veteran Member

    2,062
    5
    Mar 21, 2007
    Katy,Texas
    When running 12 in my TA it did not help, possibly because I did not address the pinion angle. New Mopar style front bias spring and stock hole hooked great.
     
  6. ULTM8Z

    ULTM8Z Veteran Member

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    May 19, 2000
    Los Angeles
    Sorry for my ignorance... What happens if you do this mod but use the stock bushings or a non spherical joint type of connection at the front eye? For a street driven Car, I like the idea of anti squat, but don't want a lot of vibration and noise in the process due to an all metal joint.
     
  7. hquackenboss

    hquackenboss New Member

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    Jan 13, 2015
    San Francisco, CA
    It still helps. If you drive it hard enough to get wheel hop under either acceleration or braking, then the trade off is hop versus a slight increase in harshness.

    I hope others chime in, but many people, including me, have had daily driver street cars with spherical bearings in suspension pivots (although I haven't personally used this one on a street car), and although there is higher impact harshness (hitting a pot hole), particularly with front lower control arm bushings, it isn't a huge issue.

    Although its an over-simplified apples and oranges comparison, if you ask me which is going to have a bigger negative impact on ride quality, solid bushings, or changing from something smaller diameter to 18" wheels with short sidewall ultra-performance tires, I'd guess the tires.
     
  8. ULTM8Z

    ULTM8Z Veteran Member

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    May 19, 2000
    Los Angeles
    And Looks like cutting the top off the front perch is ok to run like that long term?

    This is the first time I've ever seen this so I'm very curious about it all.
     
  9. hquackenboss

    hquackenboss New Member

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    Jan 13, 2015
    San Francisco, CA
    @Skip Fix,

    I want to go ask the experts (Herb Adams and Terry Satchell-- another ex-Pontiac engineer), but the pinion angle doesn't factor into the equations, except perhaps in the complexity of where the effective pivot point (the instant center) of the leaf spring really is. Although it is almost always represented as the front eye is the spring arm pivot, I learned recently that because the leaf spring is flexible between the axle and the front pivot, the effective pivot isn't exactly at the spring eye.

    The other point I wanted to emphasize is combining the spring eye mod with a longer rear shackle to raise the ride height back up to wherever you think is optimal has a small impact too.
     
  10. ULTM8Z

    ULTM8Z Veteran Member

    8,571
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    May 19, 2000
    Los Angeles
    Negative or positive impact? That's what I would end up doing to compensate for loss of ride height. I like my current ride height and would want to maintain it.
     

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