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Death Wobble Terminator

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Old Mar 8, 2011 | 04:19 PM
  #16  
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I would like to assume that the installation as well as the bar would be free of charge. I would also recommend before and after testing obviously to confirm that your design is good to go or needs refinement. Buy the way, what are your initial findings on cost? If you have one.
 
Old Mar 8, 2011 | 04:42 PM
  #17  
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Well, it all looks very good and professionally designed. However, you do not seem to be changing or doing anything to the design or geometry of the suspension that causes the death wobble, just replacing the crappy restrictive joints with nice ball joints. Improvement, yes, eliminate death wobble, no.
I see the main problem being the way the axle is connected to the radius arms, firm with no real flex.
Lets look at the ford radius arm, pivot at the frame, then two solid axle mounts above and below the center line of the front axle. When one arm(tire) moves up, it moves on the one frame side pivot, which will creat a slight rotation at the axle end. But the axle end cant rotate beacuse its firmly mounted. This will force the other side of the axle to respond, then, the original side drops or returns to normal, forcing the other side to again, follow. I'm not talking about the action of the sway/anti-roll bar, I'm talking about rotational force on the axle as it tries to move up and down. When they move together, its fine, but the left and right side fight each other when they dont move together. Kinda like hitting a speed bump or dip in the road is ok, but when one side has sudden up/down movement, things go outta whack.
Consider a popular off road long arm jeep suspension. One pivot at the frame, same as ford, but then the link arm has one joint at the axle side below the center line. Off that lower joint, another link arm comes off and attaches to the axle, above the center line of the axle and further inboard from the lower link. This keeps the pinion pointed the right way and allows one side of the axle to move up and down without creating the rotational force that fights the other side.
An even better suspension is the four link. This will allow either side to move up or down, keep pinion and caster the same, no rotation on axle tube and the link youve designed would be the fifth, to prevent lateral movement.
You can see the frame pivot, but there is not enough movement at the axle end, the axle is too "locked" into the arms movement.

Jeep style long arm kinda simulates the four link.

Ideal setup
 
Old Mar 8, 2011 | 04:44 PM
  #18  
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Sorry, forgot my main statement, the problem is not in the panhard bar.
 
Old Mar 9, 2011 | 12:38 AM
  #19  
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I would like to assume that the installation as well as the bar would be free of charge. I would also recommend before and after testing obviously to confirm that your design is good to go or needs refinement. Buy the way, what are your initial findings on cost? If you have one.
The test truck/ person would have to pay my cost of the parts and would get free installation.
What kind of "before and after testing" are you referring to?
I don't think the admins. would like if I posted prices, lets just say it will cost less than the WC kit.

Well, it all looks very good and professionally designed. However, you do not seem to be changing or doing anything to the design or geometry of the suspension that causes the death wobble, just replacing the crappy restrictive joints with nice ball joints. Improvement, yes, eliminate death wobble, no.
I see the main problem being the way the axle is connected to the radius arms, firm with no real flex.
Lets look at the ford radius arm, pivot at the frame, then two solid axle mounts above and below the center line of the front axle. When one arm(tire) moves up, it moves on the one frame side pivot, which will creat a slight rotation at the axle end. But the axle end cant rotate beacuse its firmly mounted. This will force the other side of the axle to respond, then, the original side drops or returns to normal, forcing the other side to again, follow. I'm not talking about the action of the sway/anti-roll bar, I'm talking about rotational force on the axle as it tries to move up and down. When they move together, its fine, but the left and right side fight each other when they dont move together. Kinda like hitting a speed bump or dip in the road is ok, but when one side has sudden up/down movement, things go outta whack.
Consider a popular off road long arm jeep suspension. One pivot at the frame, same as ford, but then the link arm has one joint at the axle side below the center line. Off that lower joint, another link arm comes off and attaches to the axle, above the center line of the axle and further inboard from the lower link. This keeps the pinion pointed the right way and allows one side of the axle to move up and down without creating the rotational force that fights the other side.
An even better suspension is the four link. This will allow either side to move up or down, keep pinion and caster the same, no rotation on axle tube and the link youve designed would be the fifth, to prevent lateral movement.
You can see the frame pivot, but there is not enough movement at the axle end, the axle is too "locked" into the arms movement.
I understand, but riddle me this batman, the truck I built this for has a lift kit that incorporates two separate upper and lower links with hiem joints, 2005-2007 FSD 4.5" Suspension System Stage 4 - ICON Vehicle Dynamics
Let me restate, this bar is not the cure all for all the Ford suspension issues. It's just one of the links in the chain of ford issues on this truck (Pun intended). I do appreciate your input though. Lets review the growing death wobble causes list:
-bad shocks
-shock types/brand
-tire type/brand
-tire pressure
-trac/panhard bar
-trac/panhard bar balljoint
-ailignment
-radius arms/links and mounts
-lift kits
-steering linkage and joints
-suspension possessed by satin

I threw that last one.

My 2 cents; The best 4 link set-up is one that doesn't require a panhard bar.
 
Old Mar 9, 2011 | 06:06 AM
  #20  
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When you finish your R&D and are ready to go to production, place up an ad in the "Classified" section of this forum so we can know the cost of the product.
 
Old Mar 9, 2011 | 11:58 AM
  #21  
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Well, it all looks very good and professionally designed. However, you do not seem to be changing or doing anything to the design or geometry of the suspension that causes the death wobble, just replacing the crappy restrictive joints with nice ball joints. Improvement, yes, eliminate death wobble, no.
You are missing the biggest point to my design. My set up is double sheared at the axle mount, with the joint in the center eliminating torque on the bar and joint.
 
Old Mar 9, 2011 | 12:52 PM
  #22  
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Have you thought about adding the ability to adjust the length of the track bar so you can fine tune the placement of the axle (and pivots)?
 
Old Mar 9, 2011 | 02:07 PM
  #23  
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Originally Posted by Monster-4
Have you thought about adding the ability to adjust the length of the track bar so you can fine tune the placement of the axle (and pivots)?
great recommendation!
 
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Old Mar 9, 2011 | 02:18 PM
  #24  
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When you finish your R&D and are ready to go to production, place up an ad in the "Classified" section of this forum so we can know the cost of the product.
Will do.

Have you thought about adding the ability to adjust the length of the track bar so you can fine tune the placement of the axle (and pivots)?
Well the hiem joint (tie rod end) at the frame mount will give it some adjustability, but I might have to offer a "stock" and "lifted" length rod if there's not enough. That's a question that will be answered on the test trucks.
 
Old Mar 9, 2011 | 09:32 PM
  #25  
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Originally Posted by BajaCustoms
You are missing the biggest point to my design. My set up is double sheared at the axle mount, with the joint in the center eliminating torque on the bar and joint.
???
I do get what youre saying, The questions is, how is having that type of joint changing anything. It will still travel in the same lines regardless of the type of the joint used, weather double shear or not. It will have the exact same lateral effects on the fram and axle. The existing joint can even be called double shear simply because it has mounts on either side of the joint.
Also, a ball joint certainly does eliminate the torque on the arm. Unbolt one side of my track bar and I can barely flex it up or down. Throw a ball joint on it and it will move very freely.
I mean no disrespect, and its certainly very well designed, I just wanted to know what you were getting, what your theory was and if it was just a fun little experiment. I'm looking forward to seeing how it turns out as I plan on a ball joint link arm as well.
 
Old Mar 10, 2011 | 12:50 AM
  #26  
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Batman!! (yea I gave you a knick name)
Listen up and look at the drawing below!!



I do get what youre saying, The questions is, how is having that type of joint changing anything. It will still travel in the same lines regardless of the type of the joint used, weather double shear or not. It will have the exact same lateral effects on the fram and axle.
Again missing my point. I'm concerned with the forces on the balljoint and the rod (trac bar) not the frame and the axle.
The stock setup is single shear and the bar is offset from the center of the ball joint. This applies torque on the joint and the rod. Torque can multiple the forces on each component. Look at the thin material and spring holding the stock ball joint in place. One can imagine that over time with added torque the ball joint wearing out. When the ball joint wears out deflection will occur. When deflection occurs......->DEATH WOBBLE<-
I use a uni-ball (spherical bearing) set up in double shear. The force of the rod is not offset, it is center to the ball and no torque is added.

The existing joint can even be called double shear simply because it has mounts on either side of the joint.
What are talking about? Look at the drawing.

Also, a ball joint certainly does eliminate the torque on the arm. Unbolt one side of my track bar and I can barely flex it up or down. Throw a ball joint on it and it will move very freely.
Uh, maybe your not strong enough to deflect your stock setup with your super batman muscles.

I'm trying not to come off as a punk, but please waste more of my time.
 
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