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Anti wrap bar opinions

PurfsMcGurfs said:
Did you just butt weld a c style tab to the bar and run the heims as the shackle or am I'm seeing it wrong?
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You're close, the bar has a bung in the end of it
05.jpg




It probably would have been easier to mount the second heim to the xmember and just make a simple shackle out of 2 pieces of plate, but apparently I like doing things the hard way. It's worked well though.

Edit: putting two bungs together to make both heims part of the shackle, was going to make the overall length longer than I wanted.
 
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Yeah I wanted mine adjustable for that reason, and I've adjusted it a few times over the years as I've made adjustments to the rear suspension.
Definitely make it adjustable.
 
What's the pros and cons of the two different styles of mounting the shackles? Tension and compression.
 
reptillikus said:
Edit: putting two bungs together to make both heims part of the shackle, was going to make the overall length longer than I wanted.
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That's why I asked. I was gonna say, "how the hell did you get that so short with 2 heims?"

I do like your idea with the bung and tab though.
 
SMI17 said:
What's the pros and cons of the two different styles of mounting the shackles? Tension and compression.
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Tension pulls up, compression pushes up. Tension is generally more stable since it's not trying to flip the shackle around the mounting point. It also doesnt hang down below the crossmember. Sometimes it's hard to package another crossmember below the driveshaft so you end up with a compression style setup. They both work.
 
PurfsMcGurfs said:
Tension pulls down, compression pushes up. Tension is generally more stable since it's not trying to flip the shackle around the mounting point. It also doesnt hang down below the crossmember. Sometimes it's hard to package another crossmember below the driveshaft so you end up with a compression style setup. They both work.
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Fixt
 
PurfsMcGurfs said:
Tension pulls up, compression pushes up. Tension is generally more stable since it's not trying to flip the shackle around the mounting point. It also doesnt hang down below the crossmember. Sometimes it's hard to package another crossmember below the driveshaft so you end up with a compression style setup. They both work.
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Tension will also straighten out any side to side motion whereas compression will want to increase it.

It probably doesn't matter on brodozers with thick leaf packs and high spring rates but some floppy rock crawler on flexy leaves will handle a lot better on the street without the bar trying to move about the frame side pivot point under acceleration.

gozuki said:
Fixt
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That end of the bar is always creating upward force under acceleration. It's simply a question of pushing vs pulling.
 
Ok that makes sense for the most part. For whatever reason I can wrap my brain around link suspension but the traction bar breaks it.
 
PurfsMcGurfs said:
Tension pulls up, compression pushes up. Tension is generally more stable since it's not trying to flip the shackle around the mounting point. It also doesnt hang down below the crossmember. Sometimes it's hard to package another crossmember below the driveshaft so you end up with a compression style setup. They both work.
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This is it right here. Pinion rotates up, so in tension the bar pulls up on the shackle, and on the xmember.

Ideally you want the bar flat to minimize anti-squat, but that would mean a huge low hanging shackle in compression, kind of like what youd expect on a brodozer that doesnt go offroad. Most people (myself included) aim them up towards the frame a little bit so the shackle can be shorter, and so its up out of harms way. Angling it up will increase anti-squat, but you can counter it to a certain degree by increasing the length, or changing the shackle angle. Most people will still set the shackle close to 90º so it doesnt run out of travel as the suspension moves. So its a series of compromises in order to deal with spring wrap.

Mine is angled up for rock clearance, and also because i wanted the shackle in tension so the fixed mount could be the low point. You can see it here, that nice new spray-bombed black piece just below the bottom of the frame rail:
15.jpg

I figured this was the safer bet, so i didnt have to worry about ever smacking the heims on a rock offroad. So i eliminated all my axle wrap, at the cost of gaining a bit of anti-squat. I built mine around '09 i think? So its held up well.
 
I ran anti wrap bar with shackle in compression and when the axle dropped out it moved back. Causing everything to be pulled tight and ripped the brackets off the axle. Running one now in tension with Jonny joint at the crossmember zero issues.
 
Pretty much ready to finish welding everything. I stole reptillicus' shackle design and used the 4" shackles I bought as tabs for the crossmember. I know the shackle angle is off, the heim is buried into the bar. The axle brackets arent tacked, I want to dial in the heims with enough adjustment for any future pinion changes before I permastick them on.
20230426_192715.jpg
 
I had axle hop with the bracket mounted that high up on the axle tube. But my setup was in a much shorter wheelbase. I changed the brackets to more traditional style hopping went away.

I say run it.
 
Rangerrod said:
I had axle hop with the bracket mounted that high up on the axle tube. But my setup was in a much shorter wheelbase. I changed the brackets to more traditional style hopping went away.

I say run it.
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The picture is deceiving. The bottom bolt hole of the axle bracket is about parallel with the bottom of the axle tube. I ran the bar in the top hole for more separation and a flatter top bar. It's maybe 3 or 4* up so not a very significant amount and basically flat. I figured that was the geometry I wanted to get spot on. If it drags a bit, oh well.

The Shackle design worked out better this way then my original plan. While the shackle is actually .5" longer, the mounting point is 1" lower. There's no way to tell if it'll hop until its finished but, I have a feeling this will work well.
 
I think youll be fine. Its very similar to mine, and yeah its a decent amount of anti-squat, but i dont get any hop from the rear at all. The length of the bar plays a huge part, and yours looks pretty long.
 
Rangerrod said:
I had axle hop with the bracket mounted that high up on the axle tube. But my setup was in a much shorter wheelbase. I changed the brackets to more traditional style hopping went away.
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The location of the bolts on the axle side bracket do not change the geometry of the system. The instant center is only dependent on the axle centerline and the location of the forward heim. I like the Ruff bracket because there is nothing below axle tube. I mounted everything on both axles above bottom of tube. Same for front radius arm brackets (Ballistic flat bottoms). You can play around with the 4 link calculator to see what I mean. Math is fun.

More axle separation reduces load on bushings, but again does not change geometry.

A link below axle will be in compression under acceleration. A link above axle will be in tension. A link In line with axle centerline and forward heim theoretically will have neither and puts all the force on the other link (upper). Maybe your rig is sensitive to this.
 
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rattle_snake said:
The location of the bolts on the axle side bracket do not change the geometry of the system. The instant center is only dependent on the axle centerline and the location of the forward heim. I like the Ruff bracket because there is nothing below axle tube. I mounted everything on both axles above bottom of tube. Same for front radius arm brackets (Ballistic flat bottoms). You can play around with the 4 link calculator to see what I mean. Math is fun.

More axle separation reduces load on bushings, but again does not change geometry.

A link below axle will be in compression under acceleration. A link above axle will be in tension. A link In line with axle centerline and forward heim theoretically will have neither and puts all the force on the other link (upper). Maybe your rig is sensitive to this.
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My setup was super short cj spring over. And that makes sense it might of changed the geometry when I was changing the axle side brackets. Makes sense what you’re saying.
 
I checked the numbers since I'm already out in the shop;

56" long
3.5* bar angle
Lower bolt center is 1/4" above bottom of axle tube
With the shackle angle my IC is centered under the cab.

Should work decent. I'll burn it in later.
 
PurfsMcGurfs said:
I checked the numbers since I'm already out in the shop;

56" long
3.5* bar angle
Lower bolt center is 1/4" above bottom of axle tube
With the shackle angle my IC is centered under the cab.

Should work decent. I'll burn it in later.
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before you burn it in, maybe the lower link a little below the axle because it will also take a hit before the drive shaft does. i mean maybe 1.5 inches lower or less. just an idea. :beer:
 
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