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Discussion Starter · #1 · (Edited)
Traction bar build. Slip and Twist vs shackle, tech

Just gathering parts right now... Hope to have it built this weekend.

3/4" ball x 7/8" shank heim
7/8" Jam nut
7/8" Tube Adapter
1 3/4" bushings
3/16" tabs
$120.99!



I had a couple gift cards thankfully... so baiscly free!

Next will be 10' 1 3/4" .250 wall DOM for the main part and ~2' 1 1/2" .500 wall DOM for the slip. I need to pick up a 6"-1' of 2" .250 wall DOM for the bushings.

I was going to go with Heims on the axle end but it would have ended up costing too much. With 2" .250 wall DOM I highly doubt I will have any issues issues. I have a pretty small motor and the rig is relatively light.

It will look something similar to: (Picture from Pirate4x4.com)


I have a bit of axle wrap, but I also want to protect my driveshaft more, it is taking a beating!
 

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Discussion Starter · #3 ·
The traction bar will protect the entire drive shaft, flange to flange. The diff and the housing can take it.

I plan on mounting it as close to the drive shaft as possible and about 1/2-1" lower.

Thanks for the suggestion. I'm not to worried about the diff after the traction bar is installed.
 

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hey, want to build a panhard bar for my motorhome's front axle? should be fairly easy for you. of course i will cover costs and pay you for your trouble.
 

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Discussion Starter · #5 ·
peekay331 said:
hey, want to build a panhard bar for my motorhome's front axle? should be fairly easy for you. of course i will cover costs and pay you for your trouble.
I would have to talk to my buddy. I'm using his house. I'll build it... if you design it! I don't take any responsibility on that stuff! I'll weld the hell of it, but I have never designed a Panhard.
 

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Chris, I am very interested to see how this turns out since I was looking into building my own traction bar too. Why not just go with bushings on all sides? The twist on the traction bar should take care of any radial movement when the axle is flexed.
 

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Discussion Starter · #8 · (Edited)
I want to make sure there isn't any bind. The heim is there to allow for flex steer. :)

It would have brought the cost down another ~$70.00... but well you have seen the situations I get myself into. LOL

IF I were to buy heims (rod ends?) without discounts or gift cards I would probably go through Ballistic Fabrication, or a couple other places that have much better prices than ORW down in San Diego. Luckly I had $160 in gift cards!

I'll make sure to document it the best I can for you Brian! I just wish I had a garage so I didn't have to drag the 85 over to my buddies place to burn metal, toss tools around and lay under the rig pondering my next mod that will empty my wallet. :( This would probably be almost done by the end of tonight. :banghead:
 

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so the only issue I see is when u tweak it - won't slip then.
I can send you pics of my Bud Built trac bar and it's a twisted mess.
 

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Discussion Starter · #10 · (Edited)
TBob said:
so the only issue I see is when u tweak it - won't slip then.
I can send you pics of my Bud Built trac bar and it's a twisted mess.
Bob, If I tweak it... I really have messed something up. male end will be 1/2" thick DOM, and will not have a whole lot of exposed shaft just to make sure the bending forces are reduced. Depending on price, I might even bump the female piece to .357... Depends on price!
 

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I'm interested to see how this turns out. I have been planning on building a shackle style traction bar for a while. The slip twist is definatly easier to package but my concern is it is even less adjustable than a shackle type. Seems to me that the instant center is located at the frame mount and thats it (as far as I know). With a shackle you can move the instant center slightly by altering the shackle angle. It may not make much difference at all though. :confused: Let us know how it goes. :)
 

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Discussion Starter · #12 · (Edited)
Will do!

My buddy RaideRNatioN has the BlueDevil traction bar with a shackle and it was simple to adjust.... the little we had to.

I don't see much adjustments that will be needed since I have control over the placement of each part.

Seems pretty easy to me. Maybe I'm underthinking it?

Even with a pretty flexy rear suspension the traction bars don't 'travel' much. Maybe I'm not understanding your concern?
 

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Wgasa84 said:
Will do!

My buddy RaideRNatioN has the BlueDevil traction bar with a shackle and it was simple to adjust.... the little we had to.

I don't see much adjustments that will be needed since I have control over the placement of each part.

Seems pretty easy to me. Maybe I'm underthinking it?

Even with a pretty flexy rear suspension the traction bars don't 'travel' much. Maybe I'm not understanding your concern?
My concern is in how it will affect the suspension characteristics of the truck. Mainly antisquat, since ladder style traction bars (both slip twist and shackle type) act like a radius arm they create a large amount of anti squat, this of coarse will cause the rear end of the truck to lift under acceleration. In this case I am going with the premise that too much anti squat is bad and we want to limit it. Some people like more anti squat and if you are one of those people than my argument is irrelevant :) .
With a slip twist style traction bar or a radius arm the instant center is right where you mount the link to the frame/crossmember. When you use a shackle style you can use the angle of the shackle to affect the instant centers location. By having the shackle angled like this ( front / rear ) it moves the instant center forward, I assume giving it the characteristics of an even longer slip twist bar. The farther forward the instant center the less effect the traction bar will have on lifting the rear of the truck under acceleration.
How much difference will it make??? I have know Idea. It might not make any noticeable difference at all :p , thats why I'm hoping to read your updates. :D It seems the most important thing is to make the traction bar as long and flat as possible, and that will yeild the best results.
 

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wow - think your over thinkin all this, your acting like he's 4 linking it.
The trac bar stops axle wrap - that's it. If done correctly it doesn't change the arch travel etc.. including IC RC etc...

PappaF2 said:
My concern is in how it will affect the suspension characteristics of the truck. Mainly antisquat, since ladder style traction bars (both slip twist and shackle type) act like a radius arm they create a large amount of anti squat, this of coarse will cause the rear end of the truck to lift under acceleration. In this case I am going with the premise that too much anti squat is bad and we want to limit it. Some people like more anti squat and if you are one of those people than my argument is irrelevant :) .
With a slip twist style traction bar or a radius arm the instant center is right where you mount the link to the frame/crossmember. When you use a shackle style you can use the angle of the shackle to affect the instant centers location. By having the shackle angled like this ( front / rear ) it moves the instant center forward, I assume giving it the characteristics of an even longer slip twist bar. The farther forward the instant center the less effect the traction bar will have on lifting the rear of the truck under acceleration.
How much difference will it make??? I have know Idea. It might not make any noticeable difference at all :p , thats why I'm hoping to read your updates. :D It seems the most important thing is to make the traction bar as long and flat as possible, and that will yeild the best results.
 

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Wgasa84 said:
I was going to go with Heims on the axle end but it would have ended up costing too much. With 2" .250 wall DOM I highly doubt I will have any issues issues. I have a pretty small motor and the rig is relatively light.
bushings are the devil :xdevil:
 

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TBob said:
wow - think your over thinkin all this, your acting like he's 4 linking it.
The trac bar stops axle wrap - that's it. If done correctly it doesn't change the arch travel etc.. including IC RC etc...
You're right that I'm over thinking it, I do that with everything. :D :eek:
You're incorrect in thinking that a traction bar only stops axle wrap and has no effect on the way your suspension acts. True if you build it right it won't really effect the arc of the springs through travel, but it will definatly play into if you get anti squat or not. When you put a ladder style traction bar on your rig it stops the axle wrap right? Then that means it is taking the place of the springs in that regaurd, and the springs have lost there most of their influence in infuencing the squat/antisquat. The traction bar now handles that aspect of the suspension.

A traction bar is a link. Ladder style traction bars are similar to a radius arm and a radius arm suspension is know to give somewhere around 200% anti squat, typically thats more than you want in the rear of a vehical. When you gas the truck and the traction bar stops the axle from rotating the power/energy/force travels up the traction bar/link and is transmited to the frame where the traction bar bolts up. This is now the instant center!!! This power/energy/force trys to then lift the truck. Leaf springs don;t do that on there own, all my leaf springs with no traction bar squat under acceleration.

I personally would rather my suspension have less anti squat as opposed to more. I realize that when I put a traction bar on I will be adding more antisquat than I have now, I am simply looking for the setup that will have the least noticeable effect.
Am I overthinking this... yes I am but I do that with everything. Will the difference between a slip twist and a shackle type be notice able... maybe maybe not. Will the traction bar add anti squat and will I care... yes it will and I don't know how much it would bother me once I did, but I know I'd rather have less than more, but that is the compromise of a traction bar. :)
 

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I may be totally wrong, but I'm going to have to disagree here too Todd- you're not talking about a fixed link, your talking about a slip or shackle. Any front to back transfer is going to be in the slip/twist and not factor into anti-squat- the traction bar is only fixed up front to act as a torque arm and keep the torque arm that is now attached hard mount to the axle from moving up and down, but is still permitted to move in and out. The in and out is what would cause your squat/anti-squat as it would affect the relationship of your springs shackled end to the frame.
Maybe I'm full of shit, but I think the primary difference here between what I'm interpretting ladder style to mean, like on a drag car? and this is the flex link at the frame, as opposed to a hard mount like a direct heim.

If you're putting those bushings on the axle you might as well save your money or throw it all in the trash and save your time. My front pinion rolls all over the damn place just under normal breaking, etc. with bushings at the axle- absolutely no way you're going to effectively stop wrap with bushings back there when you get on it. You need hard mounts at the axle, period.
 

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The shackle or the slip yoke doesn't releive the traction bar of the power/force/energy that casues antisquat, they are there to allow the axle to travel though its cycle and flex.
 
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