Traction bars & blocks, pics

mine at 5' almost follow the drive shaft angle
i am going to see what six does and 5.5 for angle of my bars
 
Traction bar design is just as important as material selection and installation.

TeddyBear's frame was destroyed by the combination of an offset bracket design and continous weld installation, which together allowed the axle's reaction torque to generate a side-load on the annealed frame section.

As far as length goes, 40" is about the bare minimum for compression-style traction bars (you can go shorter using them as trailing arms in a bagged 3 or 4 link with non-parallel uppers or a Watts linkage) and 100" is the practical upper limit in terms of frame mount location and beam strength vs. weight.

Although all lengths accomplish the same result, there are minor differences in how they get there! Short bars effectively push the frame away from the rear axle, resulting in more traction and a quick chassis reaction that fits well with an auto converter's driveline-cushioning benefit over a clutched truck - ideal for drag strip duty.
Long bars exhibit more front end lift, which transfers weight to the rear axle - resulting in increased rear wheel traction... also softens chassis reaction coming out of the hole (FYI for those dealing with hundreths of a second).

For sled-duty, mounting the front heim across from the tranny tailshaft is the rule of thumb, but IMO there's a certain amount of unsupported inertia in that thinking, since short bars work very well when hooking. My CR has a custom set of short bars that full-pulled the first hook - the video is on our team's webpage. Short traction bars are by nature stronger than long versions.

Long bars can give a softer ride, and work well in front of the sled providing they have a sufficient beam strength.
Small diameters, long unsupported sections and excessive weight all contribute to inadequate compressive-load capability. The set of monster bars on my twin-turbo '98 are the same diameter & length as the big 2-piece driveshafts.

IMO, parallelism to the ground or driveshaft is a tertiary consideration.
 
XLR8R said:
Traction bar design is just as important as material selection and installation.

TeddyBear's frame was destroyed by the combination of an offset bracket design and continous weld installation, which together allowed the axle's reaction torque to generate a side-load on the annealed frame section.

As far as length goes, 40" is about the bare minimum for compression-style traction bars (you can go shorter using them as trailing arms in a bagged 3 or 4 link with non-parallel uppers or a Watts linkage) and 100" is the practical upper limit in terms of frame mount location and beam strength vs. weight.

Although all lengths accomplish the same result, there are minor differences in how they get there! Short bars effectively push the frame away from the rear axle, resulting in more traction and a quick chassis reaction that fits well with an auto converter's driveline-cushioning benefit over a clutched truck - ideal for drag strip duty.
Long bars exhibit more front end lift, which transfers weight to the rear axle - resulting in increased rear wheel traction... also softens chassis reaction coming out of the hole (FYI for those dealing with hundreths of a second).

For sled-duty, mounting the front heim across from the tranny tailshaft is the rule of thumb, but IMO there's a certain amount of unsupported inertia in that thinking, since short bars work very well when hooking. My CR has a custom set of short bars that full-pulled the first hook - the video is on our team's webpage. Short traction bars are by nature stronger than long versions.

Long bars can give a softer ride, and work well in front of the sled providing they have a sufficient beam strength.
Small diameters, long unsupported sections and excessive weight all contribute to inadequate compressive-load capability. The set of monster bars on my twin-turbo '98 are the same diameter & length as the big 2-piece driveshafts.

IMO, parallelism to the ground or driveshaft is a tertiary consideration.
Click to expand...

Very good writeup! Thanks. :clap:
 
well my bars are going to be around 5-6' i plan on drag racing and pulling so i hope i that is about in the middle for a drag/pulling bar

and its going to be out of sch80 pipe or turbing i am going ot look for dom tubing tomarrow
 
cummins724 said:
Thats what I thought, till I saw this. http://www.competitiondiesel.com/forums/showthread.php?t=13189&highlight=bars+bent+frame
Click to expand...

Those bars are the ones on my truck now. In my opinion, the reason his frame bent was because of the fact that the front brackets were welded onto a non boxed part of the frame. I made a long bracket out of 3/8 angle iron for the front bracket on each side of mine. And I also mounted the bars farther forward, and higher up in the rear than what his bars were mounted. Ill post the pics when i get home, but ill be real impressed if they ever bend the frame on mine. I think it would have to destroy the frame:hehe:

All that said, i dont think you will ever have any problems from your bars/mounts. They look good.

Eric
 
Cummins Driver said:
Those bars are the ones on my truck now. In my opinion, the reason his frame bent was because of the fact that the front brackets were welded onto a non boxed part of the frame. I made a long bracket out of 3/8 angle iron for the front bracket on each side of mine. And I also mounted the bars farther forward, and higher up in the rear than what his bars were mounted. Ill post the pics when i get home, but ill be real impressed if they ever bend the frame on mine. I think it would have to destroy the frame:hehe:

All that said, i dont think you will ever have any problems from your bars/mounts. They look good.

Eric
Click to expand...

Thanks. I'm not saying shorter bars won't work, but as you can see from my pics.....I like overkill.:rockwoot:
 
My main consideration when determining the length on my bars was where on the frame I was going to attach them. I decided on the overlapped section of the frame. Right between the front door and the back door on a quad cab 3rd Gen.
 
You can also just go to your local steel yard & order some DOM tubing. If you buy 2" O.D. x 1" I.D. You can thread a set of heim joints into each end like I did. This way, you have stronger tubing, no welds to worry about, no bushings & in my opinion, a cleaner looking install.
 
Mark:
Do you have any pics of yours?

Cummins724:
Did you tap the DOM or use the threaded weld in inserts?
 
JSPulliam21 said:
Mark:
Do you have any pics of yours?

Cummins724:
Did you tap the DOM or use the threaded weld in inserts?
Click to expand...

Tapped the DOM tubing. The threads on the TSC heim joints are 1 1/8-7. You will need to do Lh threads on one side of the bar & RH threads on the other. If I were gonna do it over again, I would use the "Johnny Joints" instead of heim joints. Just make sure you order 2 LH threads & 2 RH threads.
 
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I was looking at something like this would it work?? or are they to short
i kinda like the idea so i could get a way in some classes that say no traction bars
 
I would feel safer having it hook to the bottom of the axle. More force against spring wrap.
 
trac bar pics

here are some pics of mine.
 

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Please forgive my bad pictures as i am just learning how to upload them and sizing them. Tim
 
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