traction bar

jdubb

jdubb

Well-Known Member
Joined
Apr 12, 2005
Location
Gastonia
I am almost ready to mount up a traction bar on the SOA YJ with 8.8 axle. I was thinking it would be better to have the front shackle mount as far towards the center of the Jeep as possible. Has anybody ever fabbed up a traction bar that is slightly S shaped (about 3 inches off set) to get the front part closer to the middle? Is this a waste of time or a dumb idea. Its not like it is that much trouble. I don't like the idea of one side being more flexible than the other.
 
I'm building a similar traction bar for my Bronco. The bar itself is going to be 41", which puts the shackle inline with the rear ujoint in the cv. The diff mount puts the bar in the same plane as the driveshaft. This should make the bar move as little as possible with articulation and keep my pinion angle in check. I've also been told that you don't want to create too much antisquat on the rear suspension. Especially if you have alot of engine torque. This means you don't want the rear end of the rig to raise up when you hammer the throttle. The goal should be to control axle wrap without causing the rear to be pushed down causing an unwanted bouncing condition offroad. I'm by no means an engineer nor an expert on the subject, but I have spent a lot of time the last few weeks studying, talking to others, and planning my own ladder bar.
 
If you make the top mount on your front shackle like a heim joint style mount ,it will not hurt your flex as bad as having poly joints on both..I have a tractor lift arm heim on mine ,and it moves foward and back,and side to side.Just make sure when you mount it ,the shackle is straight up and down while vehicle is sitting with all its weight on it..
 
Angle shouldn't really matter. There's probably a sweet spot for a particular setup, but I'd be more concerned about it allowing full suspension travel without binding.
 
making it s-shaped wouldn't affect its performance. The shackle *should* be vertical, so that when torque is applied, it's pulling straight up, not trying to also push the axle one way or the other..

Bucket - alot of antisquat ( >100%) is usually what causes the hopping.. if the rear end gets pushed down, that would be <100% AS, and makes the tires just spin rather than hop.

On my own setup, I've got >100% AS, and it lifts the back end under acceleration...and it hops.. dammit. EDIT: Worked it up in the 4-link calc.. ~224% AS.. :eek:
 
OK. So what will lessen this effect when designing a traction bar for YJ SOA? Is it the lonest arm possible, or the most level arm, or the axle link spacing? A little rear lift wouldn't really hurt a SOA YJ on stock springs.
 
OK so the bar needs to be in line with the driveshaft? Now I'm obsessed with getting the bar as close to the center of the axle as possible. I am considering only using one reinforced axle bracket and hanging the ends off the inside of it, dangling over the center section. Kind of silly but I can't lose what little flex I have in the back.
 
download the 4-link calculator and learn it.. That's your best bet, easiest way to do it.

Lowering the frame end has a marginal effect.. Seperating the links into what effectively becomes 1/2 a 4-link is the only way I can see to get the AS down, then you run into issues of conflicting axle arcs... ugh.
 
jdubb said:
I am almost ready to mount up a traction bar on the SOA YJ with 8.8 axle. I was thinking it would be better to have the front shackle mount as far towards the center of the Jeep as possible. Has anybody ever fabbed up a traction bar that is slightly S shaped (about 3 inches off set) to get the front part closer to the middle? Is this a waste of time or a dumb idea. Its not like it is that much trouble. I don't like the idea of one side being more flexible than the other.
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Food for thought, sorry for all the dirt.
Over a year still going strong without any major issues.

http://community.webshots.com/photo/29128196/375618695farebX
 
Hey Sheldon!

I've got a question about the traction bar in the pic. Why use a bushing at the upper mount on the rear axle? Is that just so that you can un-bolt it from the axle if you need to?

It seems to me like with that upper bushing allowing some flex, the solid bolted lower mount on the axle takes most of the stress of preventing the axle from rotating.

But if it has been in use for a year, it must work. I have seen a bunch of traction bars fail, and when they do, it usually happens the first few times out - doesn't take long for the weak point to be exposed. (Like the welds breaking on the axle, or axle brackets folding, or ripping the whole thing off the axle, leaving a hole in it...) :)
 
For those of you that have traction bar brackets welded on the axle tubes, did you dissamble the axle internals and remove bearings before welding? I was told you needed to, but I am hoping that if I just weld a little at a time and let cool I won't have to. What do yall think. I will be using a hobart 135 to weld on the brackets.
 
There's plenty of metal to dissipate the heat before it reaches the seals or bearings. I guess you could wait between each bead to keep heat off the axle tube.
 
Jones4WD said:
For those of you that have traction bar brackets welded on the axle tubes, did you dissamble the axle internals and remove bearings before welding? I was told you needed to, but I am hoping that if I just weld a little at a time and let cool I won't have to. What do yall think. I will be using a hobart 135 to weld on the brackets.
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I am gonna weld my tubes to the housing on my 8.8 and Andy at CRS told me when he does his he just pulls the cover, leaves the shafts, etc. in and welds about an inch at a time, alternating sides. You should be good to go.
 
I wouldn't think you could spin the housing with the 4.0L and 32s, but Andy may have seen this happen before. I don't have the right equipment or skill to weld to cast metal yet.
 
jdubb said:
I wouldn't think you could spin the housing with the 4.0L and 32s, but Andy may have seen this happen before. I don't have the right equipment or skill to weld to cast metal yet.
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Yes, we have seen the stock plug welds spin multiple times.......

Andy
 
I don't have to worry about welding the tubes or distorting the bearings with my 9". :smokin:

BTW...I picked up my hiem ends this afternoon. I have the axle bracket cutout, the cross member made, and the bar welded together. I still have to make a set of shackles. I also need a 4* shim to fix my pinion angle with the new Cage leafs. Anyone local have them?
 
jdubb said:
I wouldn't think you could spin the housing with the 4.0L and 32s, but Andy may have seen this happen before. I don't have the right equipment or skill to weld to cast metal yet.
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Hehe. No no. I meant when you weld your brackets on. I was just using a reference. You need more penetration to weld the tubes, and if that will not hurt the seals then welding an anitwrap bracket will not hurt either. :beer: :)
 
BUCKETOBOLTS said:
I don't have to worry about welding the tubes or distorting the bearings with my 9". :smokin:

BTW...I picked up my hiem ends this afternoon. I have the axle bracket cutout, the cross member made, and the bar welded together. I still have to make a set of shackles. I also need a 4* shim to fix my pinion angle with the new Cage leafs. Anyone local have them?
Click to expand...

I have them if you need em....

Andy
 
thecarman said:
Hey Sheldon!

I've got a question about the traction bar in the pic. Why use a bushing at the upper mount on the rear axle? Is that just so that you can un-bolt it from the axle if you need to?

It seems to me like with that upper bushing allowing some flex, the solid bolted lower mount on the axle takes most of the stress of preventing the axle from rotating.

But if it has been in use for a year, it must work. I have seen a bunch of traction bars fail, and when they do, it usually happens the first few times out - doesn't take long for the weak point to be exposed. (Like the welds breaking on the axle, or axle brackets folding, or ripping the whole thing off the axle, leaving a hole in it...) :)
Click to expand...

I used a poly bushing to allow some give otherwise you end up work hardening the whole thing and eventually something will give.
Not a perfect bar but it gets the job done and no broken yokes
to date:)

S.
 
BUCKETOBOLTS said:
Andy, guess I'll make a trip down to see/meet you the first of next week or so...
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pm's are available for a reason, and they are free too!!!
 
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