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Custom Sway bar? Hard to do? Special?

Discussion in 'The Hokey Ass Message Board' started by tokyo, May 7, 2010.

  1. I am running an idea around my head using a rear sway bar for my project.

    To give you a background - my rear is a ford 9 inch, attached to a trailing arm suspension. I See picture for details.

    I am wondering if a sway bar has to be anything special, like a certain type of steel or can I fabricate one out of solid round stock, or fab one from an existing swaybar and made to fit.

    I know I have to consider side to side travel, and up and down articulation, but other than that, is there anything else that goes into it?

    Tok
     

    Attached Files:

  2. alchemy
    Joined: Sep 27, 2002
    Posts: 15,327

    alchemy
    ALLIANCE MEMBER

    Yes they are special steel. Yes they are special sizes and shapes for a particular application. But, you can find one from a similar sized car and mount it in a similar fashion, and it should work fine.

    Or, you can make them like the roundy racers do, using splined bar and arms with links. There's a myriad of sizes to use and change to adjust and fine-tune with. Search the catalogs of the race suppliers.
     
  3. alchemy,

    thanks, i figured they were special for a reason. I will look into roundy round catalogs and see what I can find.

    tok
     
  4. missysdad1
    Joined: Dec 9, 2008
    Posts: 2,898

    missysdad1
    ALLIANCE MEMBER

    Yes.

    Sway bars have two basic purposes: limit body roll and "neutralize" cornering so that the car neither badly understeers nor badly oversteers in fast, hard corners.

    They can be fine-tuned to cause the car to intentionally understeer or oversteer to any desired degree, depending upon the track conditions.

    The purpose of a rear anti-sway bar is to aid the front anti-sway bar and are rarely if ever used alone in a properly designed chassis.

    Re: your desire to employ a rear anti-sway bar on your chassis. My suggestion would be to complete your car using a moderately larger front anti-sway bar than was standard...and hold off on the rear bar. This often turns out to be the optimum for a street-driven sedan.

    Then test-drive your car and decide if the body roll is acceptable or not. Decide also if the car understeers or oversteers when pushed in a hard corner.

    If the car understeers badly or the body roll is unacceptable, then think about a rear anti-sway bar. The rear bar will help reduce understeer and body roll by forcing the front bar to work harder. Too much rear anti-sway bar will tend to induce oversteer, which is, generally speaking, not desireable in a street-driven car. Slight understeer to neutral is generally considered optimum.

    There is much, much more to anti-sway bar technology than this, and I would encourage you to do lots of research before jumping in with both feet.

    Your best place for parts to fabricate custom anti-sway bars is Speedway Motors race car division.

    Hope this helps.

    :)
     
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  5. take a look at what Chassis engineering has to offer , they have some universal ones. on a `49 ford i did with Mustang II and 9" rear on de-arched rear springs they gave me commendations for both ends and they worked out great
     
    Last edited: May 7, 2010
  6. Well..that is certainly more than I anticipated needing to know..I will use your advice and hold off on the rear bar...and look into a larger front.

    tok
     
  7. DrJ
    Joined: Mar 3, 2001
    Posts: 9,422

    DrJ
    Member

    Your concern about body roll is real with the air bags filling off a common line.
    On turns the body roll will just dump air from the outside bag into the inside bag letting the body roll as if you only had just one bag in the middle.
    You need to separate and isolate the pressures of all your airbags to control roll even as well as steel springs do.
     
  8. Nerner
    Joined: Jul 2, 2005
    Posts: 73

    Nerner
    Member
    from New Jersey

  9. rjaustin421
    Joined: May 1, 2009
    Posts: 337

    rjaustin421
    Member

    I built a few custom sway bars for our oval track modifieds in the 70's out of the junkyard. I would fab the arms with a torch and drill them to slip over the bar and weld everything together with nickel arc rod and air cooling. Not once did a failure occur and my memory may be telling me we welded on the outside of the arm/bar only...but I do have CRS and cannot say for sure.

    You want the rear to be softer than the front which can be accomplished with either a smaller bar or the same bar diameter with longer arms. the arm length has a direct effect on the rate.
     
    Last edited: May 7, 2010
  10. dr j...it is for mock up only..I will run the valve stuff later.

    rj - thanks, that is good to know.
     
  11. WelderSeries
    Joined: Sep 20, 2007
    Posts: 762

    WelderSeries
    Alliance Vendor

    Thanks for the link... check out the videos there and if you have any questions about our kit, please let me know.

    Thanks!
     
  12. KrisKustomPaint
    Joined: Apr 20, 2007
    Posts: 1,107

    KrisKustomPaint
    Member

    Try a caprice police car they got a good beefy rear sway bar.
     
  13. inline 292
    Joined: Aug 25, 2006
    Posts: 296

    inline 292
    Member

    I have, on several of my cars now, taken a junkyard sway bar that was Very Close to what I needed, & using a large rosebud tip with gentle heating at the same time as a come-along giving a slight pull, brought in the 'arm' angles just a few degrees to narrow the connecting link centers a few inches for my application. Have street driven these cars for a few thou. miles & can not see any sign of further bending or stress in them. These have been on the front & I can say from the better roll control that they are indeed working.
     
    Last edited: May 7, 2010
  14. Astrochimp
    Joined: Sep 15, 2009
    Posts: 192

    Astrochimp
    Member
    from NE Mo.

    Stock car type- http://www.colemanracing.com/store/

    I would recommend the old book "how to make your car handle" by Fred Pund (SP?) if you want to learn the how and why stuff.
     
  15. I have done several of my old cars using factory bars adapted. On two of them I used a Mustang II front bar for the rear. It has a built in dip for the stock oil pan and it works great to dip around the rearend center. The stock Must II bar is 3/4 inch diam, good for a rear bar with a larger diam front. Most axle tubes are 3 inch diam and I used exhaust clamps to attach to the rearend, with the frame mounts bolted to the clamps. Then some simple strut extensions for the front arms.

    Easy and makes positive effect on handling. Get the bar at the self-serve junkyard and it is cheap.
     
  16. V8Mongrel
    Joined: Dec 4, 2008
    Posts: 35

    V8Mongrel
    Member
    from Apex, NC

    In addition to this source, these come up on eBay a lot. A couple of things I have found.

    1. There are units designed for the front and ones for the rear. They don't interchange easily.
    2. If you are considering tuning by running different sizes, only a small portion of the center bar is of a consistent diameter. This makes mounting the bearings or bushing significantly more difficult.
    3. In addition to the diameter of the bar, you must also consider the diameter and spline count of the ends. My advice is to watch the used market for a few weeks before buying so that you avoid getting some oddball unit.
    4. The front bars are quite wide, but this isn't as much of a problem as you might initially think because the arms can be modified to be any way you want.
    5. The bars are heavy. If you are concerned about that and have the funding, the hollow units are a lot lighter. They don't need to be much larger since the inside of the bar does very little in terms of stiffness.
    6. There are aluminum arms available. I have no experience with them, but I avoid buying used aluminum suspension parts from race cars. Just seems like a bad idea given the fatigue and failure modes of aluminum.
    Cast off race car parts are cool.
     
  17. sawzall
    Joined: Jul 15, 2002
    Posts: 4,662

    sawzall
    Member

    nice..
     

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