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Look what I made - traction bar mounts

bigburban383

1/2 ton status
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Michigan, Royal Oak
16468brackets1-med.JPG


16468tracbar-med.JPG
 
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thats pretty cool looking, where do the red boxs mount?

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Looks like below the frame to hold the rod ends.
 
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thats pretty cool looking, where do the red boxs mount?

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Looks like below the frame to hold the rod ends.

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Inside or outside? Inside the frame would be open, outside depending on backspacing and shock location there might some interferences. Are burb frames thats much different from blazer frames I'm not picturing it right? /forums/images/graemlins/thinking.gif


Also where can you get those tabs to weld onto the axle? Seen them on eBay but the guy wanted $2-3 each /forums/images/graemlins/blush.gif
 
The red box mounts are welded directly to the frame. The angle iron follows the contour of the frame (so boxes are inward). The axles mounts are then welded between the diff and shockmounts. I made them closer to help when I articulate its closer to the cent of rotation. I made those orange axle mounts, bandsaw, drill press and sander. Its just rectangle plates 1/4" x 4 1/2" x 3"
 
But wont they bind when the suspension compresses?? The axle moves in an arc from the shackle compressing and this will arc in a different direction as its mounted at the front of the axle. Or am i just an Idiot /forums/images/graemlins/thinking.gif
 
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But wont they bind when the suspension compresses?? The axle moves in an arc from the shackle compressing and this will arc in a different direction as its mounted at the front of the axle. Or am i just an Idiot /forums/images/graemlins/thinking.gif

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The axle doesnt move with the shackle movement. Though theres an arc from the pivot point of the front spring mount. The axle will just twist a little to compensate for the trac bars when it compresses or depresses...In theory in MY head...if somebody knows something that might help me please tell me.
 
On leaf spring cars that are set up for drag racing, most use something similar to this to alleviate the suspension bind.

Here is what Competition Engineering has to say about it:
"The use of ladder bars with a leaf spring rear suspension requires that the rear end housing not be rigidly attached to the leaf spring. This is because the ladder bars and the front half of the leaf spring establish two different and competing centers of rotation for the axle housing. A floating housing mount eliminates the binding and allows the housing to rotate properly."

I think you will find that the suspension will not flex very much at all, unless you accomodate the difference in the pivot points of the traction bar and leaf spring. /forums/images/graemlins/thinking.gif
 
I'll have to watch out for that bind thing, if mine bind up I'll let you know. On the other hand, since I could do over 800 on a 30* ramp with similar bars, I don't think I'll worry it. The only reason the rear stopped moving is the tire was hitting the side of the fenderwell really hard. The concept is sound.
 
Actually, as the spring compresses and the hackle moves rearward, the axle does too since the front is rigidly mounted and the main leaf must remain the same legnth. So in order for that to happen, the axle must move rearward until the spring is flat, then move forward when in negative arch. So the axle moves like this ) as the track bar tries to move like this ( . See what i mean??
 
Actually, that's not quite correct.

If the traction bar is mounted in front of the axle, it will also want the axle to travel along the radius described by the bar length, pivoting at the forward mount. Problem is, the arcs are not exactly the same so you will get some bind. To minimize the bind, the length of the anti-wrap bar should be slightly less than the length of the spring from front eye center line to axle center line. This is due to the arc distortion due to the spring flattening making the effective radius of the axle arc smaller than it might seem.
 
So your saying the shorter the bar the better. Currently these bars extend past the front spring mounts, but I do have shorter bars. Though I dont know if my brackets would still work.

Another thing with the trac bar fighting the front spring mount, wouldn't the trac bar just force the axle to twist up/down slightly?
 
No, it's not "the shorter the better" but rather "the closer the arcs the better". And yes, the binding would cause the axle to rotate, making the pinion angle change with suspension cycling. It will also bind in articulation. The amount of bind will be dependant on how the link angles and lengths work in combination. There are lots of things to consider... Using bushings rather than spherical rod ends will make things a more forgiving. As long as you are close in length you should be fine for the majority of users.
 
Stephen, if anyone is an expert in off-road suspensions, you are. I'm glad your set up works!!

There are obviously differences in drag car and truck suspensions. My buddy and I fought this kind of binding on his '77 Firebird when we added ladder bars. His ET's actually dropped after the install because the rear suspension wouldn't compress enough to transfer the weight to the rear tires, even though we eliminated the wheel-hop.

But I digress...we are talking trucks, not drag cars. /forums/images/graemlins/rotfl.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
 
ok big burban this is what you gotta do to make everyone happy go get on a ramp and measure your travel then install your traction bars and do it agin /forums/images/graemlins/thumb.gif
 
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ok big burban this is what you gotta do to make everyone happy go get on a ramp and measure your travel then install your traction bars and do it agin /forums/images/graemlins/thumb.gif

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Yeah, I guess I can answer my own questions by doing it. Maybe even help you guys find out if my trac bar setup style works.
 
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