Moving front spring eyes rearward

Suspension, Steering and Chassis

  1. rw@cuda1haub

    rw@cuda1haub Member

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    Beside being able to install larger diameter tires, advantage or dis-advantage of moving front spring eyes rearward? Whats normal or maximum amount allowed? I have read some of 3/4 or one inch. I think it would move rear hangers to a bad angle?
     
  2. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    The only reason I would ever do that was if the rear axle was crooked side to side.....and then I'd look for the difference to be in a frame rail or the unibody of the car before I even considered moving the spring brackets. I've just never thought it was a good idea. Beside the bad rear shackle angle, it will also pull the drive shaft out of the transmission tail shaft a little.
     
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    • clementine

      clementine Flight risk FABO Gold Member

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      If a guy was looking to move his wheels back in the wheel well and was in the process of installing sliders, He wouldnt have to worry so much about shackle angle. Pulling the driveshaft out too far would be a concern as previously noted.
       
    • rw@cuda1haub

      rw@cuda1haub Member

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      I am installing an A518, so have to change driveshaft length anyway.
       
    • toolmanmike

      toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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      Racers do that to keep the front of the slicks out of the wheel openings. There are threads here about the subject and Mancini I believe sells extended front spring hangers. 1/2-3/4" makes a big difference.
       
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      • toolmanmike

        toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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        Here's a thread I had bookmarked. There may be more. This link starts on page 2 I believe. Moving rear axle back
         
      • RustyRatRod

        RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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        So everybody does it and that makes it cool. Not for me. Not something I'll ever do.
         
      • Locomotion

        Locomotion Well-Known Member

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        The "allowed" amount comes from class racing rules, like NHRA Stock & Super Stock. It limits the amount of difference from OEM specs as well as difference from side-to-side. Some racers staggered the wheelbase from side-to-side to gain more rollout, thus giving faster ETs. Made it difficult for good, consistent RTs.
         
      • famous bob

        famous bob mopar misfit

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        Agree , will make slightly less weight on the rear wheels too , opposite of moving them forward , like the early afx cars !-bad idea to me , altho some have done it .
         
      • famous bob

        famous bob mopar misfit

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        I made a pass in a fairly well known mopar superstock racers 67 belvedere once , he had the front wheels staggered for a starting line advantage and didnt tell me , was dam hard to control without knowing it. I turned the same et as he did tho---------
         
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        • famous bob

          famous bob mopar misfit

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          Looks like it would be if the sliders bottomed out to the rear ----------
           
        • mopowers

          mopowers Well-Known Member

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          If you're installing tall enough tires to warrant moving the rear axle backwards to gain tire clearance, you're probably going to be relocating the leaf springs as well anyway. Since relocating the leaf springs will require moving the rear hangers to the frame rail (some choose to install sliders), it's really not much more work to move them back to match how much you moved the rearend.

          You just want to make sure the hanger is angled back slightly at ride height to allow enough suspension travel without hitting the frame at full squat, over bottoming out forward with the suspension at full droop.

          An alternative is drilling new holes in the mounting pads on the axle tubes and shock mount plates to move the axle back a tad.

          What size tire are you trying to run?
           
        • RustyRatRod

          RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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          If I just HAD to have "that" big a tire, I would reshape the front of the wheel well before I moved the springs.
           
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          • toolmanmike

            toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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            That's like overhauling the engine when all you need is a tune up. :poke::rofl:
             
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            • RustyRatRod

              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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              Or it's just another way to accomplish the same thing. I've just never liked the idea of changing the wheelbase. Polish it up however you want, that is what you're doing if you change the spring position.
               
            • ir3333

              ir3333 Well-Known Member

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              1/2" - 3/4" won't even be noticed.
               
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              • rw@cuda1haub

                rw@cuda1haub Member

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              • rw@cuda1haub

                rw@cuda1haub Member

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                Thanks for the info. 72 Scamp, installing 405 h.p. 360 Magnum, A518, 323 sure grip, just wanting to get all the tire under it I can.
                 
              • mcodecuda

                mcodecuda Senior Member

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                The rear ended of a Plymouth can be moved back a inch by using front spring hangers from a Dodge.
                 
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                • 33IMP

                  33IMP Well-Known Member

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                  Mine are moved back an inch on my b-body. Wouldn't hesitate a second if i had to do it again. More centered in the wheelwell, and room for a 30" tall tire. Re-drilled super stock hangers.
                   
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                  • famous bob

                    famous bob mopar misfit

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                    ______________________________

                    I hit the agree button , I did it .
                     
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                    • RustyRatRod

                      RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                      "I" would notice it and "I" would know about it. It would bother me.
                       
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                      • famous bob

                        famous bob mopar misfit

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                        moving them back creates a little less weight on the rear wheels , if u have any traction problems , it aint gonna help !
                         
                      • toolmanmike

                        toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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                        Wish I knew how far the second car has been moved back. 3/4" would be a guess.

                        70 swinger.jpg2 (1).jpg

                        70 swinger3 (1).jpg
                         
                      • famous bob

                        famous bob mopar misfit

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                        thumbnail - Copy (2).jpg
                        Sure wouldn`t have helped this !---------]16 x32 1/2'' stones .
                        moved forward 2'' w/ 002-003 superstock springs , after it was painted , u couldnt tell it , unless beside another one .
                         
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