wrap/ trac bar (1 Viewer)

[dustin]

I am still trying to visualize the dynamics of the antisquat. I am not sure how obvious it is or if it was mentioned before... Doesnt the frame side of the mount want to swing up, not down? Atleast thats what it looks like from my broken one. So the bottom tube of a latter style bar is pushing, and the top pulling at the frame side when under load. Is it that action of the frame side of the bar pushing up that raises the rear of the rig up? And so, the more horizontal the bar is, the less leverage it has on pushing the axle away from the body.. Or am I getting this all mixed up?

thanks!
Dustin

 

[FLYINGLOW]

Doesnt the frame side of the mount want to swing up, not down? Atleast thats what it looks like from my broken one. So the bottom tube of a latter style bar is pushing, and the top pulling at the frame side when under load. Is it that action of the frame side of the bar pushing up that raises the rear of the rig up? And so, the more horizontal the bar is, the less leverage it has on pushing the axle away from the body..

The frame end is mounted to keep the bar from rising up (up or down travel = axle wrap) with forward torque and down with reverse torque. The torque of the axle acting on the bar gives you anti squat. The higher it is mounted on the frame the more antisquat you get (the rear of the truck will rise up with too much giving wheel hop) and the lower the bar is mounted the less A/S you get (the rear of the truck will squat with too little and give brake hop). This is with forward torque, reverse torque will give you the opposite effect.

 

[dustin]

yea. I am struggling with understanding how the height of the mount matters. Would a more horizontal bar torque more forward to back, then up and down?

thanks!
Dustin

 

[FLYINGLOW]

yea. I am struggling with understanding how the height of the mount matters. Would a more horizontal bar torque more forward to back, then up and down?

thanks!
Dustin

The torque would be in an up and down direction. The axle wants to rotate opposite the direction of the tires which would torque the front mount of the bar up in forward gear and down in reverse gear.

If you make a bar like Woody's then you should be in the ball park and can't go to wrong.

 

[awp_cruiser]

I have a question.

In Trollhole's post the wrap bar is below the shackle. This one from Sam's Offroad is above the shackle. Is one method of attachment better than the other?

 

[bustanutley]

lower mount provides protection for the drive shaft, lower also = a lower antisquat #

 

[bandy rooster]

beer in a bottle, genius!

 

[dustin]

I finally finished my wrap bar. So far it seems to work well. I flexed the rig out last night and the bar seems to not bind. I need to do the test with it unbolted from the front shackle to be sure.

This bar is made from 1.5" OD, .25 wall DOM. I have 5/8 heims at the axle side, and a 3/4" heim up front with misalignment shims, and takes a 5/8 bolt. That is attached to a shackle I made which is hooked off a 3/4" bolt welded to the same DOM used on the bar with a bushing that takes a 5/16 bolt. The shackle hangs from my t-case mount- which is bolted to the frame with 5/8 fine thread bolts. Its length is adjustable. The shackle can swing forward toward the T-case a full 3 inches. About 2 inches further than it will ever swing. However, this mounting point makes me a little nervous that the upward force on this cross member is so substantial and will break the mounting bolts.

The design of the bar and this shackle will allow me to swap the bushing side out with the front heim if I need to. I think the front heim is best though, since it allows the bar to twist, whereas if the shackle hung from the heim, it would have to swing to allow the bar to twist on it. Blue Torch Fab does it that way, and I have heard that heims are really designed to be used that way- push pull, than how I am currently running it, which may cause it to shear. We'll see... I may end up on version 3 of my wrap bar in no time.

On road manners of the rig have improved. I used to get alot of axle wrap with 37's and 55 springs on the 40. On the throttle, it used to squat alot. That seems to be gone, though I did feel it start to lift up yesterday under heavy throttle. So I can see wheel hop now introduced into the rigs characteristics. I also feel the bar banging the frame a little as its doing its thing. Its taking some getting used to. Maybe a bigger/ thicker bushing will help. I also lost some ground clearance. I am trying to convince myself its okay, since it sorta protects the driveline..

So- whatcha think about this fix point at the t-case. I leave for Rubithon in a week. Guess I will really find out then.

cheers!
Dustin

 

[bad_religion_au]

what about this wrap bar setup (2 bars???)

 

[Full_M3tal]

Ok... Obivously If You Have SUA The You Really Dont Need Anti Wrap, Spring Do It For You.....

Now On A SOA It Is Only Needed For 2 Anti Wrap Arm On The Bottom Of The Axle, Top Of Axle Is For Reverse And Bottom Is Drive Gear.... Now If Your Slamin It In Reverse And Seeing How Hard You Can Pop The Clutch In Reverse Then I Can Under Stand The Ladder Bar Setup....

Also Do Not Put Shackles On A Single Arm, It Wont Help Anything.

Tractor Parts Work Great For This Item....

 

[Mace]

Ok... Obivously If You Have SUA The You Really Dont Need Anti Wrap, Spring Do It For You.....

Now On A SOA It Is Only Needed For 2 Anti Wrap Arm On The Bottom Of The Axle, Top Of Axle Is For Reverse And Bottom Is Drive Gear.... Now If Your Slamin It In Reverse And Seeing How Hard You Can Pop The Clutch In Reverse Then I Can Under Stand The Ladder Bar Setup....

Also Do Not Put Shackles On A Single Arm, It Wont Help Anything.

Tractor Parts Work Great For This Item....

No,

Even SUA you can have wrap issues. It is just compounded by putting the lever on the outside of the curve instead of the inside of the spring during a springover..

When you only run arms on the bottom (or the top) of an axle you are typically asking for trouble. You are relying on the leaf spring to complete the "link". And, since the distortion of the leaf spring is what we are trying to avoid because it is not up to the task, it will never truly work.

To control the rotation of a axle, you need to have 2 points basically opposed to each other on the axle and connected to the frame. Ladder bar is the easiest way to do this..

A 80 series gets away with doing 2 bushings at the axle on one arm. This is similar to the Early Bronco Radius arm setup. It works, but I have seen more of these styles fail due to the arm just not built strong enough. And, the 80 style single arm needs a shackle.. Unless you can design the perfect length arm that follows the imperfect arc that a leaf sprung axle takes...

 

[Ullr]

bump

I am looking for tubing recomendations. I am going to use Woody's design with 5/8" heims at teh shackle/crossmember end and at the upper axle end. What is a good tubing size for 5/8" heim? I know Woody specs 1" OD 3/16" wall DOM but Dustin used 1.5" OD .25" wall DOM. Do I need to thread it?

 

[bustanutley]

just weld a nut on the end and use a jam nut. Mine is made out of 1.5"X .12 hrew and 1.5" X 3/16" box. No issues

 

[Ullr]

I am thinking of finding a tubing thats tappable (is that a word?), as in close to the ID I need for the tap, so the heims thread right in.

 

[bustanutley]

that is a mighty large tap.

www.mcmaster.com

 

[rusty_tlc]

I am thinking of finding a tubing thats tappable (is that a word?), as in close to the ID I need for the tap, so the heims thread right in.

Weld in bungs from spidertrax or bluetorch fab would be easier and cheaper than buying the tap.

BTW DOM is malleable enough to tap, folks like All Pro use it to make drag links and tie rods.

 

[Full_M3tal]

No,

Even SUA you can have wrap issues. It is just compounded by putting the lever on the outside of the curve instead of the inside of the spring during a springover..

When you only run arms on the bottom (or the top) of an axle you are typically asking for trouble. You are relying on the leaf spring to complete the "link". And, since the distortion of the leaf spring is what we are trying to avoid because it is not up to the task, it will never truly work.

To control the rotation of a axle, you need to have 2 points basically opposed to each other on the axle and connected to the frame. Ladder bar is the easiest way to do this..

A 80 series gets away with doing 2 bushings at the axle on one arm. This is similar to the Early Bronco Radius arm setup. It works, but I have seen more of these styles fail due to the arm just not built strong enough. And, the 80 style single arm needs a shackle.. Unless you can design the perfect length arm that follows the imperfect arc that a leaf sprung axle takes...

Yea True On That Mace, On The SUA, If Your Spings Are Soft Then Yes You Will Get Axle Wrap, But With The Spings On The Bottom It Creates Less Axle Wrap....

SUA With Stock Spring Will Alow Some Movement With The Pinion, If Your Hoping Really Bad Yes Most Defently You'll Brake Something....

SOA With No Traction Bars On Bottom, Or Like A Anti Wrap Item Of An Kind On The Axle With Stock Springs. Put Your Truck In Drive/ 1st Gear Low Range . And Power Brake It And Have Some One Watch You Pinion Move.... You Wont Need To Do This If You Have Alcan Spings, The Have A Extra Spring To Help With Anti Wrap.... Dont Slam On The Gas And Expect TO Roast* Some Tires.... Do It Slow So You Can See It.....

Now On Traction Bars Tractor Links Work Fine, Just The Thread Get Messed Up Over Time....

Tubing Is A Great Idea, But Why Not Just Do A Four Link?

Or You Can Do It Shackle Style, Shackle On A Sturdy CrossMember, With two Points On Axle, Like The 80's Front Axle Design For The 2 Link...

Really Make Want You Want, And Happy Building

Just My .02 cents

 

[Trollhole]

So far my 50 dollar antiwrap bar is working fine. I love tractor parts. lol

 

[Trollhole]

Damn, that's funny. I've been running one of those TSW bars as a single non-shackled bar with my my SUA for 3 years and it's worked decent with a similar top tower on the axle. Getting ready to add a ladder type as I'm going SOA - I'm not at home to check, but I thought the housing was aluminum - did you mig with gas to put the 2 together?

Damn I wish I would have seen your response earlier.

No the tractor link was made out of steel. I just cut off the ends and machined them down to fit inside the tube about 6 inches then welded.

The ironic thing about my wrap bar is you were the one who said I really neaded one bad. Only after 3 months of having wrap and braking issues did I really understand what you meant and the I made this one by copying to some extent what Woody did.

The ironic part is I saw your bar at Jims before Tellico and thought there was no way your pinion was going to make it. I feel bad for not saying anything. Since you had given me good advice the year before. My bad.

 

[lowtideride]

Damn I wish I would have seen your response earlier.

No the tractor link was made out of steel. I just cut off the ends and machined them down to fit inside the tube about 6 inches then welded.

The ironic thing about my wrap bar is you were the one who said I really neaded one bad. Only after 3 months of having wrap and braking issues did I really understand what you meant and the I made this one by copying to some extent what Woody did.

The ironic part is I saw your bar at Jims before Tellico and thought there was no way your pinion was going to make it. I feel bad for not saying anything. Since you had given me good advice the year before. My bad.

What are you taking about He got the best dressed award while changing it on the river floor with me, jim and steve