Better anti wrap ideas? (2 Viewers)

[Mace]

Unfortunately there is almost no way to completly eliminate some sort of binding with an axle wrap bar. The axle does not travel in a perfect arc or line or anything for that matter.

Given what is available as a way to mitigate axle wrap, and the broken pinions that are associated with it the simple ladder bar is the best solution. Unless you want to put another shackle on each leaf spring and link the entire truck

It most certianly is not perfect.. But, it does work.. Replacing old landcruiser springs when they wear out slowly is a hell of a lot easier than replacing a pinion on the trail..

 

[ntsqd]

The axle does travel in an arc, it just is not one with a constant radius. A very sharp friend of mine measured the horizontal and vertical distance from the axle to the front spring eye bolt at different points in the travel range on his Early Bronco and then plotted them using SolidWorks. His simple method could be used on graph paper too. What he found was the radius of the arc wasn't consistent, but that it did not vary by a lot. He was also able to plot the approximate "pivot point" of the arc (it isn't the front spring eye bolt). Parametric CAD helps there because of the ability to make circles of unknown radius equal in diameter. If you measured 3 points, then where the equal circles centered on those 3 points all intersect is the virtual pivot point. If they won't intersect, then the center of the sort of triangular area defined by them is the average location for the pivot point.

Once that point's location was known then a simple single bar link can be used. This puts the main leafs in compression under acceleration rather than bending them into an S curve. Since the axle mount necessarily wants to be above the axle centerline the frame end mount needs to be offset the same distance. Same is true if the axle mount has to be slightly forwards or backwards of the axle centerline.

For EB's the kit already exists, Wild Horses calls it the "Wrap-Trap."

 

[Mace]

The wrap trap is very similar in design to the Deckers Hot Camp Showers Bar.

And is not the best design IMHO.

It essentially uses the leaf springs as a second link. If you have soft springs, you will still experience axle wrap due to spring deformation.

That unit helps a lot. But is far from as strong as a A frame bar that attatches to the axle in two places. You can easily break a pinion with that design.

 

[lowenbrau]

I thought the bam bar might be the answer but it still causes the leafs to go 's' shaped and wear out fast. I'm thinking for the amount of engineering and fab work, I'm better off just building a four link on bags for the rear and being done with it.

 

[cody c]

im debating about building one of these as well, can anyone tell me the ideal length for the main or upper tube like fj40 garage built (stock re-arched springs in back) also can i build something off of a frame rail or do i gotta build a beam between the frame rails.

Also considering one for the front of the cruiser as well.
Thankyouwho.

 

[D'Animal]

ntsqd

Thanks for posting the picture and graph up. Measuring the arc of the axle when moving up and down on a vehicle lift is one thing. I want to build and install a ladder bar system that will save my pinion when I am up climbing up against a rock ledge (waterfall) and have to give it some gas. The springs will distort and the pinion angle goes out whack and snaps.

 

[D'Animal]

Can someone please explain to me what Gary was thinking when he did this?

Yes, I'm serious.

 

[Butt Ugly Chuck]

I am running the 63" chevy 1/2 ton srpings on my rig. They are long and soft.

D',
Are you running those SUA? My stock springs are a little saggy and I'm exploring options. 63" Chevys seem to be a pretty inexpensive way to go (compared to OME), but a search on them returns mostly SOA applications. I'm not ready to go there.

Sorry for the highjack...
Butt

 

[ntsqd]

The wrap trap is very similar in design to the Deckers Hot Camp Showers Bar.

And is not the best design IMHO.

Concur, however there IS no best design. Every single possible option has plus' and minus'. The minus of the A-link is that it kills springs. The single link works the springs harder than stock, but nowhere near as hard as does the A-Link.

It essentially uses the leaf springs as a second link. If you have soft springs, you will still experience axle wrap due to spring deformation.

It's a question of degrees. Lars has soft Deavers and from observation on the trail they do not wrap-up.

That unit helps a lot. But is far from as strong as a A frame bar that attatches to the axle in two places. You can easily break a pinion with that design.

I've yet to hear any any issues at all with this design. The A-link tries to lift the front of the truck. The single link tries to pull it back. Both place large loads on their axle brackets, but the A-Link puts bending loads into the link where the Single link only puts in tension. Steel is much stronger in tension than in bending.
Mine is not a popular position. I blame PoOR-washing on this.

D'Animal, I think that you're looking at a 4 link. If you made two of the A-links and floated the housing on the springs or double shackled them you'd get part of what you want, but you'd give up articulation. I do not know that it can be done with only one. Putting all of the torque reaction into one is asking for a well designed system. Anything less will be either massively over-built (HEAVY) or be fragile. Regardless, I suspect that at this point some form of lateral location will be needed.
No pic?

A-link or single link, the ideal frame end pivot point would be where I described it above.

If success is defined as it lives for one year, then perhaps the A-link is a success. I define success as I don't ever have to come back to it except for maintenance. Nothing that I've seen inspires me to think that the A-Link is capable of this.

 

[D'Animal]

D',
Are you running those SUA? My stock springs are a little saggy and I'm exploring options. 63" Chevys seem to be a pretty inexpensive way to go (compared to OME), but a search on them returns mostly SOA applications. I'm not ready to go there.

Sorry for the highjack...
Butt

I'm SOA and these are on my FJ45 project build. I'm at 122" wheelbase.

I highjacked someone elses thread so we are even.

 

[Butt Ugly Chuck]

For what it's worth, one of the advantages to the 63" Chevy's touted here on Pirate is you can use the front half of a Chevy overload spring to prevent axle wrap.
Butt

 

[Mace]

Concur, however there IS no best design. Every single possible option has plus' and minus'. The minus of the A-link is that it kills springs. The single link works the springs harder than stock, but nowhere near as hard as does the A-Link.

It's a question of degrees. Lars has soft Deavers and from observation on the trail they do not wrap-up.

Deavers for broncos are also what, 8 or 9 soft, very thin leaves?? How much arch do they have? All things to consider here.

A SO cruiser using soft, flat springs wraps something fierce.. A single bar is better than nothing. And yes, most likely the spring will last longer with this design. However you run the risk of snapping pinions. It happens with LC's. Read around and see.

Here is a Jeep Youtobe video that shows what happens when you run no or just one link.

http://www.youtube.com/watch?v=Hv6HZVv4GUo&NR

 

[D'Animal]

This is gonna be Red Neck as any thing but, I have a vision in my head of what I think I need. I'm going to make a mock up using water pipe.

I will post pics here and we can discuss what I need to change. I'm may just be duplicating a crappy design that I saw in a magazine while in the library.

Next question DOM or HREW or Chrome Molly? What Diameter?

 

[CruisinFJ60]

hehe water pipe...

nice.

 

[D'Animal]

I'm going to make a mock up using water pipe.

hehe water pipe...

nice.

For mock up only.

 

[ntsqd]

The video link is good at showing why a lower link needs to have diameter. In either a 4 link or an A-link the lower tube is under compression and the upper tube is under tension. No news there. Steel doesn't really like compression, it favors tension. Tension only requires a suitable cross sectional area. Compression needs diameter. Coincidentally the lower tube is the one most likely to contact a rock. If that happens while under a load it is exactly like standing on a soda can and then tapping the side. So the lower tube not only has to have some diameter working in it's favor, it also needs to have some wall thickness going for it. The upper link could literally be a piece of suitably sized cable if backing up under power never happened.

What is misleading in the video is that the upper link's frame end isn't in the right place. The various forces involved are not balanced and the main leaf bends as a result. I won't say that had the pivot been in the correct place that the main leaf wouldn't bend, just that it would not have bent nearly as much.
EB's commonly use either 10 leaf spring pack or an 11 leaf spring pack if they have their HT on. Lars has the HT in place. There is probably 4"-5" of arc in the springs, but EB's are a tension shackle design with a significantly offset center pin, so the main leaf is fairly close to flat btwn the axle hsg and the front spring eye. Might be 2" of arc at most.

DOM, CREW/HREW, or 4130? They all weigh the same. The seam in CREW/HREW is an issue for the lower tube, not so much for the upper. 4130, fabricated correctly, requires some form of post welding heat treat or a very specific welding method to avoid a brittle HAZ. I'd use DOM for the lower and either of the mild steel options for the upper.

 

[D'Animal]

So a standard MIG will not weld 4130?

 

[Mace]

So a standard MIG will not weld 4130?

It will, but the area around the weld is prone to cracking. Most of the Chromo chassis you see were welded with a mig. Is it the proper way to do things? Nope.. But it is done all the time.

Just use mild steel. mine was 1.5" square tubing. The arm never failed even with grogan doing 2nd gear grabs on the pavement testing out the turbo...

It is more a design issue than material issue.. If you make a Y shaped link, most likely it will fail at the vertex of the two legs..

ntsqd, there is no place that you could put that upper link that would have prevented the spring from bending.. All you could do is modify the arc that the axle would rotate around. The jeep springs and the cruiser springs just cannot handle being the secondary link at times of high traction..

An 11 leaf pack is going to be a heck of a lot more resistant to axle wrap than a 5 or 6 leaf design..

Post up pics of the water pipe Dan

 

[ntsqd]

So a standard MIG will not weld 4130?

It will weld it. Commonly done.

What isn't commonly known is that 4130 becomes brittle in the HAZ unless either Normalized or the weld is done in a certain manner. I'm not convinced that this certain manner yields acceptable results (& though I can guess, I'm unfamiliar with the exact process), but I've been told by a claimed veteran fab guy that it does work.
My method, if I had to MIG weld it, would be to use an oxy-fuel torch to soot the area around the weld and then heat that area until the soot burned off. Then weld it. Then repeat the sooting and heating. After all of that I'd let it cool in still air.

Welds are on-site castings. Anything that you can do to make the metal grain size smaller is a good thing.

4130 was designed to be Oxy-fuel welded. Any process with a higher heat concentration causes the area around the HAZ to not be warmed high enough. This results in the colder surrounding metal acting as a quenching agent. Not a lot different than dropping a freshly welded part into a bucket of water.
Some guys do a rosebud Normalize after welding, but that is imprecise at best. Takes a LOT of experience to be consistent and get the desired results.

If you're a weight-weenie where every ounce counts, and the whole rig has been carefully Engineered and designed then maybe 4130 makes sense. In some critically loaded parts 4130 might make sense. The density of 4130 is the same as mild steel, the only gain that 4130 offers is it's higher strength meaning that you can use a thinner wall for a part of the same strength. I don't see the extra cost & effort of 4130 making sense in a traction bar where you probably want some wall thickness anyway. Unless bragging rights are important.

 

[ntsqd]

If you think about it, the only leaf really loaded as a link is the main leaf. The others are not connected at both the middle and the end. The other leaves may offer some support, but it is really up to the main leaf. So it doesn't matter if it is 3 leaf spring or a 37 leaf spring.
If the force vectors are correctly arranged then the loads are balanced and counter-acting. If the force vectors are not correctly arranged then things will break.
It is, unfortunately, a compressive loading. Better would be a tensile loading, but that means that the link has to be a hangy-down part.