my traction bar/skid setup

Figured I've talked about this stuff enough, and I finally got it done and a little testing done. Figured everyone else posts their mods, so why don't I for once. My long debate with goatman a while ago made me move the traction bar mount up forward rather than at the leaf mount, and it seems to be working well, it's about 2' behind the crossmember.

I got a little wheel hop on one climb, but that could be since I had no shocks whatsoever in the rear. I can only notice some anti-squat when I floor it out of a turn, but it's not bad. The shackle shoots through the floor, and the mount hangs no lower than the frame rail, while the crossmember hangs only 1" below, so it's tucked up nicely. Here are some dirty pics, hope you can make some of it out...I forgot to take pics when it was nice and clean.


Traction bar mount showing shackle through the floor, kinda hard to see.


Skid showing traction bar mount on the left, and x-memeber on right


axle mount with 3"x2" poloy bushings


Showing clearance


one more with t-bar angle and mount


I skimped on a few things as I was in a rush to get it done for wheeling last sunday, but not horribly. Going back to fix the little things once I get more time. _nicko_

Sweet:thumbup:

What things do you want/need to change on it? I am still planning/trying to find time to build my traction bar.

AARON

Nothing is getting "changed" really, just things like mounting bolts, extra bracing (pretty much angle iron) and that stuff. The only thing I'm pissed about is that I rushed the actual traction bar and it warped from welding. So the bushings holes aren't a perfect match with the holes in the axle mount. It took some persuading to fit.

Oh yeah, and boxing up the huge hole in my floor. I used duck tape to close it up for now. _nicko_

What are you doing to allow it to swivel when your axle articulates? Richard has the double heim joints on the front instead of a shackle. Wish I would've done that. It looks like the perfect solution.

My front joint threads into the end of the traction bar and has a jam nut that I need to loosen when I go off-road. I forgot to loosen the jam nut a while back and bent the axle bracket pretty bad.

I put a REALLY soft rubber bushing in the shackle (repro 68 camaro leaf spring bushing), rather than the stock rubber, it's ridiculously soft. I defintiely have thought about the swivel. Hopefully this will be fine. If not, I've seen people make shackles that have two perpendicular swivels to it (side to side, and front to back). I'm sure I could mangle one of those up pretty quickly. Maybe I will do it anyway just to be safe. I should be able to get to that this weekend.

here we are, just got this off pirate real quick.

gearwhine said:

here we are, just got this off pirate real quick.

Click to expand...

That's the ugliest bit 'o fab I've seen in a long time. Too bad it works or I could talk some smack.

BTW, I'm referring to the pirate pic, not yours'. :wave:

-jb

What modifications brought on the need for a track bar? I noticed you had the shock mounts removed from the axle, which in stock form helps to prevent axle wrap, but your tire size and spring set-up really doesn't look like it necessitates a track bar (am I missing something?). Just curious...

Keep in mind your changed anti-squat when you hit the trail. Mine is built at similar angles to yours and in some situations it works very well (steep, high traction climbing) and in others it is horrible (looser traction ledges). In the bad situations it wants to hop pretty badly.

I'm changing to a bam bar setup on my new housing.

CRASH

CRASH said:

Keep in mind your changed anti-squat when you hit the trail. Mine is built at similar angles to yours and in some situations it works very well (steep, high traction climbing) and in others it is horrible (looser traction ledges). In the bad situations it wants to hop pretty badly.

I'm changing to a bam bar setup on my new housing.

CRASH

Click to expand...

What do you mean by "bam bar"?
Chad

CRASH said:

Keep in mind your changed anti-squat when you hit the trail. Mine is built at similar angles to yours and in some situations it works very well (steep, high traction climbing) and in others it is horrible (looser traction ledges). In the bad situations it wants to hop pretty badly.

I'm changing to a bam bar setup on my new housing.

CRASH

Click to expand...

Oh gawd...not a bam bar!

Long arms AND a bam bar?

Is a bam bar WCGIC approved?



I'm just looking forward to you being able to come out and play.

vintagespeed said:

That's the ugliest bit 'o fab I've seen in a long time. Too bad it works or I could talk some smack.

BTW, I'm referring to the pirate pic, not yours'. :wave:

-jb

Click to expand...

Two hiems is pretty simple.........and a lot better looking.

Capt. Nemo said:

What modifications brought on the need for a track bar? I noticed you had the shock mounts removed from the axle, which in stock form helps to prevent axle wrap, but your tire size and spring set-up really doesn't look like it necessitates a track bar (am I missing something?). Just curious...

Click to expand...

you are missing something. I did a YJ shackle set up in the rear, and removed a leaf out of my leaf pack(so I didn't get any extra lift). So I was afraid of geting some wrap now with less leafs. I do do tough trails for the size of my jeep, so the traction my tires can get (33") can still hammer my springs (they are almost flat at static height, so that makes it even worse). I do have to replace the taken out leaf spring though, as it gets weighed down to almost nothing with all my trail equipment.

Also, Shock mounts are there, they are tucked up on the tube. The reason I have no shocks now is because with the equip weighing the rear down, plus raising the shock mounts, my shocks were bottoming out on every bump I hit.

CRASH said:

Keep in mind your changed anti-squat when you hit the trail. Mine is built at similar angles to yours and in some situations it works very well (steep, high traction climbing) and in others it is horrible (looser traction ledges). In the bad situations it wants to hop pretty badly.

Click to expand...

OK, Yeah, The place I noticed hop was a small ledge where it was quite slippery with dirt and loose rocks. I'll have to try it out some more, and learn how it reacts.

bam bar...... :gag: from what I see, that thing can't help that much. It will act just like a single bar on top of your diff. It has one pivot point, which can still rotate the pinion up. I can see it helping a tiny bit since it wants to force the axle housing forward on power, that's depending on the springs to stop it from moving (so you get some unwanted bow in the front half of your springs). However, I may be wrong, those are my impressions of it, and have never seen it in action.

vintagespeed said:

That's the ugliest bit 'o fab I've seen in a long time. Too bad it works or I could talk some smack.

Click to expand...

I think I'm gonna make a 1/4 elip. type shackle, half heim, half normal shackle. Will work with the RE joint, have the side to side swivel, be nice and solid, have adjustable height and should look prettier (that's all that matters doesn't it?) than 2 heims, and that weird double bushed shackle thing. _nicko_

bam bar...... :gag: from what I see, that thing can't help that much. It will act just like a single bar on top of your diff. It has one pivot point, which can still rotate the pinion up. I can see it helping a tiny bit since it wants to force the axle housing forward on power, that's depending on the springs to stop it from moving (so you get some unwanted bow in the front half of your springs). However, I may be wrong, those are my impressions of it, and have never seen it in action.

Click to expand...

http://www.jeepaholics.com/tech/bambar/

Are we talking about the same thing? The link above is what I'm talking about building. I have seen it work VERY well, with little effect on anti-squat.

CRASH

definitely talking about the same thing. I've read that whole write up before. I just found this diagram to show what I'm talking about.



This coming part is MY interpretation of what it will do, I have not read this, and have not seen it work...so read on if you care.....

It IS a ladder bar, just a REALLY short one. Think of the antisquat of a typical long lader bar with the joint up in front of the axle...it wants to push the axle down (blue straight line in ladder diagram).

Now move that same exact ladder bar, same length and all up perpendicular to the ground. Under torque it will want to push the axle down relative to the ladder bar, but now since it's above the axle, it's going to push the axle forward (not down). That is why you don't get "true" antisquat, because the antisquat is acting in a different direction (forward, as shown with the straight blue line on the axle), which in part will put stress on the front half of your leaf spring.

Now add in the shortness of the bar. It's still going to pivot around that joint, wheter it's above the axle, or in front of it. So, now you have stressed leafs from a force wanting to move the axle forward. If that force (torque) is great enough, it will bend the front of your leaf springs, and get pinion twist up because it's going to pivot around the joint above the axle, which is the same thing your traction bar is supposed to stop.

So in short, it still puts wrap stress on the springs, just relieves it a little bit.

I hope my logic is right....anyone else? _nicko_

P.S. Also, if you ever took a class in statics or solids...you know the sum of the forces equal zero. With the ladder bar, you have a force going up at the shackle, so you need a force going down to counteract that force(anti-squat).

Now with the bam bar, you have a force pushing back (blue line at shackle), and you need an equal but opposite force to counteract that (force at axle point forward)...causing the spring to take the brunt of the force.

the "bam bar" is essentially the same thing as a single bar. the axle will want to rotate around the point at the end of the shackle, the only thing preventing it from rotating about that point is putting the front half of the leaf spring in compression (assuming forwards motion). I don't like this setup because it is still making the leaf-springs do work (other that supporting the vehicle).

This has been well hashed out on PBB also.

This is not to say it doesn't work, but it is the same as a single bar, and it is still putting tension/compression loads on the leaf springs.

okay, gearwhine beat me too it, and he's right on in his explanation

gearwhine said:

P.S. Also, if you ever took a class in statics or solids...you know the sum of the forces equal zero. With the ladder bar, you have a force going up at the shackle, so you need a force going down to counteract that force(anti-squat).

Click to expand...

I do have a very slight problem with this statement however. You will not neccesarily get anti-squat with a ladder bar, it all depends on where the front of the bar is mounted. You will always have "lift" at the point it is mounted, and in most cases it is mounted far enough back that you do get anti-squat, but imagine if you were to have the shackle mounted by the front bumper.

I am going to build a "slip n twist" syle bar for my MJ. It's basically a ladder bar, but instead of using a shackle and a rodends, you just mount the front with a regular bushing and at the front of the bar i'm going to put some round stock that fit's just inside some heavy wall DOM. The slip accounts for the different arc of the leafspring vs the ladder bar, and the twist accounts for articulation.

mad maXJ said:

I do have a very slight problem with this statement however. You will not neccesarily get anti-squat with a ladder bar, it all depends on where the front of the bar is mounted. You will always have "lift" at the point it is mounted, and in most cases it is mounted far enough back that you do get anti-squat, but imagine if you were to have the shackle mounted by the front bumper.

Click to expand...

exactly. It's kinda the same concept as the seperation of the bushings at the axle end I guess. The further you seperate them, the less force the bracket will get.

If you lengthen the traction bar, the seperation gets wider, and you will have less forces acting on the shackle, meaning less anti-squat forces. There will never be absolutely none, even if mounted 1 mile in front of your car, but it will be close to non-existent, and you won't feel it or notice anything. _nicko_

At this point, I'm willing to let the leaf springs take some load off of my axle tubes. The driver's side tube has taken an awful beating, torn open once, and spun in the housing once, even after welding it.

The new housing will have an over the top truss that will be welded to the center section, hopefully this will help spread the load of the standard ladder bar setup. I think I will try to move the ladder bar up a bit to decrease the AS before I try something different.

In any case, here's my setup:





CRASH

damn, Thatbar has taken a beating with all your tube problems. It adds a nice futuristic looks to it though with all the bends.

Another good option would be to get/make a nice thick rock ring (3/8" to 1/2") and attach it to the truss your making rather than welding it to the housing...It looks...."trick" that way too.

I welded one side of my bracket to the diff housing. I'm not too trustworthy in my welds to cast yet though, The first time I did it, I saw all these tiny spider web cracks. then I preheated the housing and went ahead with it...I didnd't see any cracks, so hopefully it's all good now. Once I get my bender set-up I'll be making a truss as well. so then I shoudl be all worry free.

_nicko_