Anti-Wrap Q's

[GLTHFJ60]

I've got some free time. Maybe I'll go out to the local OHV and shoot some under-body video and photos of my setup.

Please do. I'm interested in seeing your bar in action. I tend to agree with Mace because he's advocating for what the vast majority of land cruiser owners have, but I want to learn more about how your theories work in reality.

Take some videos and post them up!

 

[Fast Eddy]

I ran a good number of the hammer trails without a antiwrap bar (sprung over) one year. Just because it has not failed does not mean it is a solid design.

No question. Good point. I don't wheel all that much.

Springs matter too. I've got a full set of fj62 rear springs in the rear. If I had a set like my reduced fj55 rears I have in the front the rear end would wrap a lot worse.

Allowing the threads to turn every time you articulate is a very bad idea. It will blow out the threads eventually. It may take a long time to happen, but the amount of dirt, rust, mud that gets in there will wear it out.

I'll bet greased threads will last as long as any other part of the suspension. My bar also will allow moisture to collect in some metal-on-metal crevices. It will have to be serviced every once in a while. If I go shoot video I'll tune it up and take some pictures before I go.

The shackle allows for front to back movement. If you bolt it directly to the x member, it will kill the springs even faster or rip off the x member.

I don't believe there is any front to back movement, or very little. The tip of the bar, unshackled, would travel in a pattern kind of like an oval, perpendicular to the pinion. The side-to-side travel and the mount for the tip of the bar has to take this into account.

 

[chicago]

The rotational movement in the wrap bar would be accounted for by the spring bushings at the axle ends of the wrap bar and in the x member shackle hanger (not In This set up cuz he used heims, but those who do use them) and the front to back movement would be allowed by the shackle.

Ed.
Ill be curious to see how your set up holds up down the road. If you're doing fire roads and easy trails here and there, I think it'll be fine, but if you start wheeling harder trails more.... I just don't think it's gonna hold up unless your springs are controlling wrap really well.

 

[Fast Eddy]

The rotational movement in the wrap bar would be accounted for by the spring bushings at the axle ends of the wrap bar and in the x member shackle hanger (not In This set up cuz he used heims, but those who do use them) and the front to back movement would be allowed by the shackle.

What about the up-and-down movement? The tip of the bar travels straight up and down. If he's going over whoop-de-doos the whole weight of the axle and tires is hanging from that shackle. Y'all want to think that the suspension rotates down and away from the tip at the front heim, but it doesn't. The triangle of the bar doesn't tip down and back. The whole thing moves straight up and down, or at least it would if it wasn't bolted to the x-member.

Even worse, when the rig is loaded up with gear, the tip of the bar at the front heim needs to be able to move straight up. What then?

 

[GLTHFJ60]

What about the up-and-down movement? The tip of the bar travels straight up and down. If he's going over whoop-de-doos the whole weight of the axle and tires is hanging from that shackle. Y'all want to think that the suspension rotates down and away from the tip at the front heim, but it doesn't. The triangle of the bar doesn't tip down and back. The whole thing moves straight up and down, or at least it would if it wasn't bolted to the x-member.

Even worse, when the rig is loaded up with gear, the tip of the bar at the front heim needs to be able to move straight up. What then?

Is that what you're achieving with your shackle pointed down along the length of the main wrap bar instead of being vertical when mounted? Wouldn't that then pull the axle forward when flexing up or down (as the shackle arches up and down)?


For the shackle inversion problem, why not use an anti-inversion shackle, like on leaf springs?

 

[74fj40ca]

I was under the impression that the shackle is used to allow movement when the axle droops or compresses on the springs, and the side to side movement is allowed by the heim joint at the end of the bar.

I'd be curious to see a video of a anti-wrap bar in actual movement. I love all the talk about anti-wrap bars, gives me some good ideas.

I wouldn't be using it, but after my SOA, I get crazy amounts of axle wrap, of course, the springs are original the '40, which probably doesn't help.

 

[Mace]

What about the up-and-down movement? The tip of the bar travels straight up and down. If he's going over whoop-de-doos the whole weight of the axle and tires is hanging from that shackle. Y'all want to think that the suspension rotates down and away from the tip at the front heim, but it doesn't. The triangle of the bar doesn't tip down and back. The whole thing moves straight up and down, or at least it would if it wasn't bolted to the x-member.

Even worse, when the rig is loaded up with gear, the tip of the bar at the front heim needs to be able to move straight up. What then?

The up and down movement is exactly what a anti wrap bar is designed to control.

If it can't, the driveshaft will bind and snap the pinion.

Ladder bars are not the best solution. They put a pretty good stress on the leaf springs. However, the alternatives have not proven to be better yet.

 

[GLTHFJ60]

The up and down movement is exactly what a anti wrap bar is designed to control.

If it can't, the driveshaft will bind and snap the pinion.

Ladder bars are not the best solution. They put a pretty good stress on the leaf springs. However, the alternatives have not proven to be better yet.

He's talking about when the suspension cycles up and down, without torque wrap, the pinion remains at the same angle, more or less, throughout the travel of the suspension. When the ladder bar is attached to the pumpkin but not at the shackle, the ladder bar would remain somewhat level, but move up and down with the axle. When the ladder bar is attached to a fixed shackle, as in a shackle that's pointed straight at the ground, this movement is restricted. That's what this image is talking about. Dotted lines are a ladder bar that's attached to the shackle. Solid lines are a ladder bar that is not attached at the end.

I think this is the effect that Fast Eddy is talking about mitigating with his modified ladder bar design. That's why I want to see more pics and videos of it in action.

 

[Fast Eddy]

Is that what you're achieving with your shackle pointed down along the length of the main wrap bar instead of being vertical when mounted? Wouldn't that then pull the axle forward when flexing up or down (as the shackle arches up and down)?

My bar telescopes, that's the beauty of it. Neither the torque nor the up-and-down movement of the axle can cause it to bind. The telescoping part also twists inside the main tube so articulation can't cause it to bind either.

When there's axle twist the tip pulls out and the shackle goes up to the limit of it's travel, then stops. With a 3" shackle and a 36" bar that would allow 5 degrees of twist at the pinion; well within the specs of the u-joint. If it twists in reverse it can go 5 degrees in the other direction.

For the shackle inversion problem, why not use an anti-inversion shackle, like on leaf springs?

It would work. I used the parts I had on hand. I thought about welding some tabs on the shackle I used, then I wouldn't need a return spring.

I'd be curious to see a video of a anti-wrap bar in actual movement. I love all the talk about anti-wrap bars, gives me some good ideas.

I agree. It will answer a lot of questions. I'm on it.

The up and down movement is exactly what a anti wrap bar is designed to control.

Ladder bars are not the best solution. They put a pretty good stress on the leaf springs. However, the alternatives have not proven to be better yet.

Not the up-and-down, but the twist. Up-and-down is what happens to the rear end when you hit some whoops; both springs going up and the axle drooping.

He's talking about when the suspension cycles up and down, without torque wrap, the pinion remains at the same angle, more or less, throughout the travel of the suspension.

I think this is the effect that Fast Eddy is talking about mitigating with his modified ladder bar design. That's why I want to see more pics and videos of it in action.

Yup. That diagram from Decker's site is what originally got me thinking about this from a mathematical point of view.

 

[Mace]

That diagram from Deckers is nice and all but it's wrong.
This diagram he has:

Describes the pinion movement. Because the axle is mounted forward of the center pin the pinion rotates up during droop and down when stuffed.

I was able to unbolt my old ladder bar in my 40 with the axle almost fully extended. There was about 1" of offset to get it back in place. The frame side of the ladder bar does not travel up and down like the axle does.

I can see your "allowable" deflection ending up being similar to a dead blow hammer one day.

Also, I know of three people off the top of my head that have had their lower links stripped out because they only locked down one side of the link. It's the same reason your steering TRE's have some sort of lock on both threaded ends. But it's your call.

 

[GLTHFJ60]

I was able to unbolt my old ladder bar in my 40 with the axle almost fully extended. There was about 1" of offset to get it back in place. The frame side of the ladder bar does not travel up and down like the axle does.

How does the end of the bar move when the axle is flexed up and down?

 

[Fast Eddy]

Also, I know of three people off the top of my head that have had their lower links stripped out because they only locked down one side of the link. It's the same reason your steering TRE's have some sort of lock on both threaded ends.

Steering TREs are locked on both ends because they are opposite threaded and the alignment depends on the tie rod not turning.

You're saying the threads pulled out of the threads in the tube? I'm surprised. How much thread?

 

[Mace]

How does the end of the bar move when the axle is flexed up and down?

The end of the bar does not really need to that much.

the axle rotates during compression and extension. That reduces the amount of vertical movement that the frame end of the bar has.

Steering TREs are locked on both ends because they are opposite threaded and the alignment depends on the tie rod not turning.

You're saying the threads pulled out of the threads in the tube? I'm surprised. How much thread?

Suspension links are opposite threaded (if built correctly) as well. If you lock one end down, there is not enough movement in the second rod end (or TRE) to make any real difference. less than 1/8th of a turn or so.

Inch and a half or so of thread engagement. 3/4" heims. That slight wobble that threads have to their :nut" wears the softer metal down over time, and slip..

 

[Fast Eddy]

Suspension links are opposite threaded (if built correctly) as well.

Not true of the wrap bar though. I see what you're saying about it wobbling around and eventually wearing and pulling out.

You could treat it as a wear item and replace it once every couple years.

 

[GLTHFJ60]

Not true of the wrap bar though. I see what you're saying about it wobbling around and eventually wearing and pulling out.

You could treat it as a wear item and replace it once every couple years.

Mace is saying that the threads pulled out of the thread insert I believe. If that's the case, cutting off and welding on a new insert is pretty labor intense to do every couple of years and not correct it.

If you have a joint with enough flex, I don't see why you can't nut it in place.

 

[chicago]

LOL!!
can beat this debate any more to death!!

 

[Mace]

LOL!!
can beat this debate any more to death!!

Nope

It comes down to this.

If you have a new design. Please, by all means build it and take some video of it working (either on the rocks or with 5 grand dumps on the pavement). Show us how and how well it works

 

[Fast Eddy]

If you have a new design. Please, by all means build it and take some video of it working (either on the rocks or with 5 grand dumps on the pavement). Show us how and how well it works

Yup. Not sure I can wind the 2f up to 5 grand though.

 

[rusty_tlc]

Think all those cut outs in the brackets had anything to do with it?

 

[Mace]

Yup. Not sure I can wind the 2f up to 5 grand though.

Mine does