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Hot Rods pan hard bar with leaf springs?

Discussion in 'The Hokey Ass Message Board' started by HOTRODPRIMER, Nov 26, 2018.

  1. seb fontana
    Joined: Sep 1, 2005
    Posts: 8,442

    seb fontana
    Member
    from ct

    ""Also note...the "half length" bars (as attached to the center section of the differential) are to be avoided unless you limit the up and down travel to a small minimum.""

    I don't think its as bad as thought..The
    '48s had Panhard at front and rear..
     
    HOTRODPRIMER likes this.
  2. This could very well be the problem. HRP
     
  3. I have run a diagonal bar on a set of ladder bars and it was good in a straight line and normal turning, but when you started doing donuts or slides it was under immense stress and not as good a panhard in my opinion.
     
  4. One thing not mentioned is a leaf/link suspension. Triangulate the upper bars and you've got your sideways motion controlled. Added plus is tunable traction control.
     
  5. The37Kid
    Joined: Apr 30, 2004
    Posts: 30,628

    The37Kid
    Member

    1896-Panhard_et-Levassor-8hp_DV-08_PBC_02.jpg
    Panhard bar named after the car manufacturer that invented it. This one was built in 1896, big & littles were common back then. Bob
     
    Last edited: Nov 30, 2018
    Bandit Billy likes this.
  6. I'm going to try and do some adjusting tomorrow, I have a few ideas that have been suggested that my work , I drove the car around the block this afternoon and the tire rubs the lip of the fender when turning to the left, someone in the past has worked on the lip and they are flat on both sides. HRP
     
    Last edited: Dec 3, 2018
  7. Slopok
    Joined: Jan 30, 2012
    Posts: 2,919

    Slopok
    Member

    It takes 3 rights to make a left!:rolleyes:
     
    Johnny Gee likes this.
  8. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,602

    Johnny Gee
    Member
    from Downey, Ca

    My Mom drove like that. I can laugh about it now but not so funny back then.
     
    gimpyshotrods likes this.
  9. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,906

    Kerrynzl
    Member

    Mythbusters did an episode on that :D
     
  10. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    Your mom was on to something. UPS does that, and I have a ton of data at work that proves UPS, and your mom are absolutely correct in doing that.
     
  11. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,602

    Johnny Gee
    Member
    from Downey, Ca

    Oh no! Anxiety, Bipolar Disorder and OSD. No wonder packages get broken. ;):)
     
  12. Slopok
    Joined: Jan 30, 2012
    Posts: 2,919

    Slopok
    Member

    If your Moms name is Helen, that was my Moms best friend!
    Funny.... I didn't think many would understand.
     
    Johnny Gee likes this.
  13. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    Please don't post my medical records here.
     
    Chavezk21 likes this.
  14. 1962 comet gtr
    Joined: Aug 24, 2018
    Posts: 48

    1962 comet gtr

    I have run a Panhard bar on rear of leafspring cars many times over the years without any bad handling issues, only improvements in handling. Understanding how leafsprings respond in corners, spring bushing flex, spring deflection, etc. My experience has usually involved a Falcon based chassis, street driven often on twisty back roads, but once on the rear of a 1978 Corolla that was street & track driven. I always choose to keep it simple & inexpensive, fabricating everything in house, go with OEM rubber bushings to offer the least resistance (binding) & rubber works just fine on car mostly street driven, choosing my ride height, ( lowered 2 to 2 1/2 inches), using axle drop limiters ( designed to quickly disconnect so axle will drop far enough to change a flat tire), @ ride height have the bar inline with axle tube for most street driving, however make the mounts adjustable up & down from there at both ends for tuning). My cars usually get set up more like a sports car, corner handling of importance to me because I love traveling in the Northwest Of the USA & avoid Interstates like the plague, prefering the twisty scenic routes as much as possible. & sometimes I show up at the local autocross as well. I,ve calculated about 3/8" movement left to right when moving axle up & down through the allowed travel, static testing of course. Unexspected plus- Significantly reduces the effect of high buffeting side winds.
     
    Desmodromic likes this.
  15. 1962 comet gtr
    Joined: Aug 24, 2018
    Posts: 48

    1962 comet gtr

    Latest project. Will have a 1" square tube running diagonally to a frame bracket on other side, spreading the force @ frame in a similar fashion. Have never had problems with frame cracking or deflecting, and I periodically put em to the test! panhard brckt mounted 10-26-2019 001.JPG panhard brckt mounted 10-26-2019 004.JPG
     
    Last edited: Jan 12, 2020
  16. 1962 comet gtr
    Joined: Aug 24, 2018
    Posts: 48

    1962 comet gtr

    Axle bracket, used 3" exhaust tube for jig. panhard bar axle bracket 11-4-19 003.JPG
     
    Last edited: Jan 12, 2020
  17. 1962 comet gtr
    Joined: Aug 24, 2018
    Posts: 48

    1962 comet gtr

    235/60R14 fits 1962 comet well without narrowing axle using a Maverick V8 axle housing & Torq Thrust D VN105 with 4.42" backspacing. Room to spare. Inside trunk reveals reinforcement to well to make up for lost integrity from removing the formed outer portion of well. Also, some structure from roll bar will end up tying into "frame rail" next to rearward portion of well keeping things fairly tight. 3-26-19 002.JPG
     
    Last edited: Jan 14, 2020
  18. Just use the "edit" function to go back and delete the extra pics. You can do that anytime, even a year later.
    -------------------------------
    A bunch of people assumed HRP wanted to use a Panhard bar to force the axle to center. (?)
    I didn't. I assumed he just wanted to prevent any shift that was enough to rub.
    What was the final outcome of all this?
     
  19. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,799

    jimmy six
    ALLIANCE MEMBER

     
  20. 1962 comet gtr
    Joined: Aug 24, 2018
    Posts: 48

    1962 comet gtr

    Thank you for the guidance concerning deleting... Also, that is what I thought as well. My post was for those that were indicating that Panhard bar was not a good idea on leaf spring cars. A lot of ways to skin a cat...
     
  21. 1962 comet gtr
    Joined: Aug 24, 2018
    Posts: 48

    1962 comet gtr

    Jimmy Six-Oh for sure, as pictured. When completed this will have a diagonal bar running to frame @ other side to keep it from folding/twisting, also hard to see, fabbed U-channel where attaches to frame, & bolt holes in frame have tubes welded across. I can't say for dirt trackin, but this set up, or similar (with diagonal bracing) has been used on road courses a time or two. But, yes, dirt trackin has a way of bringing everything to the brink of disaster. Sure is fun though!
     
    Last edited: Jan 14, 2020
  22. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,230

    Mimilan
    Member

    ^^^^^^^^
    No it isn't.............Look again.
    The lower bar is a panhard bar attached to the leaf spring and the upper bar is a diagonal brace

    On Left turning dirt cars, you want the panhard bar to have compression loads not tension loads.
    So it needs to be mounted on the LH side of the frame and RH side of the axle.[with adjustable heights]
    By steepening the angle of the panhard [from horizontal] lateral acceleration loads get transfered into vertical loads on the RR tyre [also known as "side-bite" in dirt terminology]
    The panhard bar is a tuning tool.

    The panhard bar needs multiple height pivot holes at each end.
    1: to adjust the angle ^^^ as above
    2: to raise and lower the whole bar so the roll-centre can be raised or lowered.
     
    gnichols likes this.
  23. A Boner
    Joined: Dec 25, 2004
    Posts: 7,419

    A Boner
    Member

    Tires too big?
     
  24. 1962 comet gtr
    Joined: Aug 24, 2018
    Posts: 48

    1962 comet gtr

    Mimilan- I get that. Are you responding to my post? My post was in regards of a modified unibody falcon based chassis built for street & spirited driving that would be turning left & right on everything from crappy farm roads to decent two lane blacktop, 300 to 400 net HP, etc. I haven,t been involved in dirt circle tracking since our local track went to asphalt in 1989.... Yes, on dirt or other loose media (we had a wonderful recipe of sticky gray clay mixed with sand) the panhard bar would need to be positioned to "stick" the outside tire downward by transmitting the weight of the car from left side of frame through the panhard bar to the outside right rear tire... Damn, I wish we still had a dirt track.. Some of the best racing I ever got to see & on occasion participate as a driver happened at that track. Redwood Acres Raceway, Eureka, Ca.
     
  25. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,671

    jaw22w
    Member
    from Indiana

    I had forgotten about this thread. You are correct, of course. I looked at the thing too quickly.
     
  26. LAROKE
    Joined: Sep 5, 2007
    Posts: 2,079

    LAROKE
    Member

    The builder of my '37 put a panhard rod on but the weld broke and I took it off a few years into my ownership. Later, I was surprised to find my O/T '91 Jeep Rengade came from the factory with one. Made me rethink things and I may put the '37 rod back on in a future build. I think the break may have been due more to axle wrap than lateral forces.

    [​IMG]

    [​IMG]
     
  27. 1962 comet gtr
    Joined: Aug 24, 2018
    Posts: 48

    1962 comet gtr

     
  28. 1962 comet gtr
    Joined: Aug 24, 2018
    Posts: 48

    1962 comet gtr

    I think axle wrap may have contributed to the breakage if binding is occurring, but I suspect lateral forces. Torque motion should move heim freely if it's not binding, just swinging the bar back & forth in an arc, more or less. Lateral forces are brutal on the other hand. Also, having a tall bracket (distance from axle to panhard mount) plays a part, in the stresses involved, due to lateral forces (that is a long lever with a tiny base). Is the heim joint binding, etc. The mounting area where weld is needs to be braced in a fashion so the bracket has more area to be welded @ axle housing (a bigger triangle on all four sides of bracket). Maybe the bracket base should be cut to wrap around 1/2 of axle tube. this would support the bracket much better as positioned spreading the forces out over a much wider area @ axle tube & give more weld area. Make sure the hiem joints are not binding in any direction as well. OR! Maybe it was a weld with poor penetration although it appears it broke above the weld. Or metal too thin or the metal crystalized, happens sometimes when the metal cooled too fast after welding, like hitting it with cold water right after weld completed etc.... Things to ponder.
     
    Last edited: Jan 14, 2020
    LAROKE likes this.
  29. LAROKE
    Joined: Sep 5, 2007
    Posts: 2,079

    LAROKE
    Member

    Thanx for the help. The truck is a '37 Chevy with Jimmy 302 inline six, about 230 hp and 300 lbft of torque feeding thru a T5 five speed to a standard '57 Chevy rear end. A future engine swap for the truck is a '54 Buick 322 nailhead with Latham supercharger I'm still gathering parts for. If that happens, I'm thinking about putting the panhard rod back on in combination with a ladder bar for axle wrap as I'm also thinking of installin a positraction unit in the axle.

    [​IMG]

    [​IMG]
    My apologies to the OP for taking his thread off on a tangent.
     
  30. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,230

    Mimilan
    Member

    Compare your bracket to the triangular shaped bracket on the Jeep. That is the cause of the breakage plus your Panhard bar is too short [in theory the Jeep Panhard is also too short but it will have rubber bushes in the ends for compliance]

    Now please understand this with semi-elliptic leaf spring suspension. The up/down movement of the LH wheel pivots [or arcs from] the RH spring.
    The up/down movement of the RH wheel pivots [or arcs from] the LH spring

    So a panhard bar with pivots at each end is the "Most correct" form of locator for this type of suspension [better than Watts links etc which pivot in the centre]
    Ideally you would want the pivot points directly above the leaf springs [but this is sometimes an engineering impossibility]

    Your vehicle has Bump stops AND Lowering Blocks
    So if the suspension Bottoms out ,there is still a lot of room between the bottom of the Frame rail and the top of the Leaf spring.

    Try and put the bar behind the axle and lengthen it to the same width as the Spring Base.
    Most importantly! Carefully measure the Frame bracket so it is just shy of touching the spring when bottomed out.
    And the axle bracket should be just shy of touching the frame when bottomed out.

    These are just the brackets, not the locating holes in them. Try and get them so the frame pivot height is 1" higher than the Axle pivot height at normal ride height.

    A tape measure, Dummy cardboard brackets [and duct tape] are your friend here.
     
    LAROKE likes this.

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