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2 more anti wrap bar ideas

Discussion in 'The Garage' started by cegusman, Jun 26, 2003.

  1. cegusman

    cegusman 3/4 ton status

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    Why would this not work? I don't see where any binding would happen. It should not limit any flex either.

    Anti Wrap Bar #1

    Would this on just be to weak?
    Anti Wrap Bar #2

    /forums/images/graemlins/k5.gif
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    System one counts on the leaf spring for triangulation. Under applied power the upper shackle wants to stretch, but it can't. The front half of the leaf spring wants to compress, and in many cases it can. If it's soft enough to need a bar it's soft enough to distort into an S shape...creating bad anti-squat and prolly doing almost nothing for anti-wrap. The stiffer the springs the better this one would work. Then again the stiffer the springs the less you need an anti-wrap bar.

    Number two has much the same problems...single bar or single link anti-wrap systems do not work very well. At the most they will supress some wrap, but usually they will also induce bad anti-squat.

    Rene
     
  3. 69K5

    69K5 1/2 ton status

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    i like the second one but not the first. the first looks like they are trying to over complicate life.

    nathan
     
  4. backyardbuilt

    backyardbuilt 1/2 ton status

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    The top one looks to be well thought out and very functional. As for the bottom one Looks pretty cheesy. I want to hear what borregok5, 45acp/and jr, and other good fabricators have to say though. I could build the top one I think. which would save me alot of $$$$$$.
     
  5. BorregoK5

    BorregoK5 1/2 ton status

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    If your springs have a heavy arch or relatively stiff spring with a minor arch to them, then both of those would work. Where they become questionable is when your running a flat spring which is soft where bars like that can in fact force a spring to wrap up. What happens is the axle from the center line up tries to rotate back on acceleration. If you have a solid beam holding it still on top, you create a pivot point which pushes the bottom of the axle forward since the solid beam can not lengthen or shorten. In a link setup, this bottom bar is where you transfer that force into lift back at the frame (anti-squat) but if that link is a flexible spring, you force it to bow or wrap up. The reason it works on a relatively stiff positive arched spring is its ability to resist that force which would have inverted it. When you take that same link and place it below the leaf spring, the opposite happens and it tries to stretch the spring, keeping it flat. The advantage to a single bar setup which works more on acceleration and less on deceleration is the improved braking characteristics. Take the ladder bar for example: By fixing a bar to both the top and bottom of the axle and moving that rotation forward on the vehicle, the rotation the axle sees under acceleration pushes up on the vehicle (anti-squat) and effectively forces the tires down, but on deceleration the exact opposite happens and effectively pulls the tires up which results in less traction. This is one reason you really need to limit how much anti-squat you generate and why it is important to have longer beams.

    Early autocross cars figured this out quickly and decoupled their torque bars with either a Reese bar (shock on the frame end instead of shackle) or a telescoping upper bar as shown here:
    [​IMG]
     

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