Read before replying search!:flipoff2:

At the last ERoCC comp, I tore the wrap bar mount off the axle (bad welds). I just finished the new one, and installed stock 7 leaf waggy springs moving the axle back a couple inches.

I started mocking up the new ladder bar today and am concered with spring bind at full droop and to some extent when the axle is articulated side to side. With my mock up and the front rod end not attached to a mount, I cycled the axle from loaded at rest to full droop. The front end of the mocked up bar moved down 4-5" and forward 1"!

I don't see anyway with a normal ladder bar setup (with the shackle up or down) to handle that movement with out bind the springs.


To avoid this, I started thinking about building some slip into the front of the ladder bar (say about 4") and using a short ( < 2") shackle mounted above the bar. This would allow the bar to shorten/lengthen as necessary but still control the wrap.

The slip would be either sleeved tubing, or a modified slip yoke and spline from a driveshaft.

So the questions are: Do you think this would work? Would the slip shaft be strong enouch to deal with the torque from the axle wrap tendancy? Anyone doing anything similar?

See below for the general idea. RED is where the slip would be mounted.

Thanks for reading :D :beer:

use a shackle and let it bind a little. maybe make the shackle longer than normal? ;)

Dah! Guess I'll partly answer my own post... It will still bind. Just spent some time looking at it. The slip isn't going to address the binding issue.

I am probably making this more complicated then it needs to be.

a slip like that would allow the spring to wrap in an s formation? a friend of mine once set up bars on the top of the spring plate to the frame just at the front of the leaf.......it seemed to work..... but what do i know i never really did much with leafs :shrug: you should be gettin something in the mail real soon

I'm assuming that you have the bar mounted just outside the housing. (close to center as possible)
I was figuring on a two part shackle with mine, similar in design as what H8Monday did with his.
So as much as I hate to say it..................
Maybe try a search under his name. He posted up pictures of it a while back.
I can't see how a modified slip yoke can help you, but a shackle set up that put's you in mind of a revolver shackle might.
Good luck.

Originally posted by doctor_G
I was figuring on a two part shackle with mine, similar in design as what H8Monday did with his.

Yep. And add a little length to the sahckle if you're concerned with how much it moves.

as far as i know there are only 2 ways to control wrap with little to no binding, the first is to fab a single wrap bar, mounted above the axle center and slighty above and forward of the spring hanger, if the numbers are right this mimicks the natural arc produced. the second would be a 2 link, you can use the same mounts you have on the axle, but make two mounts on the frame with two seperate bars, again the numbers have to jive to mimick the arc produced.

Originally posted by RHINO
as far as i know there are only 2 ways to control wrap with little to no binding, the first is to fab a single wrap bar, mounted above the axle center and slighty above and forward of the spring hanger, if the numbers are right this mimicks the natural arc produced. the second would be a 2 link, you can use the same mounts you have on the axle, but make two mounts on the frame with two seperate bars, again the numbers have to jive to mimick the arc produced.

I'm running the single bar setup mentioned above. I don't have any binding problems, but the single bar design does allow for a little wrap. It is not enough to cause the spring to unload and hop. I'm very ahppy with it.

I saw a system a few weeks ago that I like. I'm thinking of using it myself. It used a standard ladder bar type arm mounted near the center of the axle using 2 spring bushings. The other end, where a shackle would normally be, was a bushing mounted with the bolt horizontal and perpendicular to the frame. On the bushing was mounted a drive shaft slip shaft receiver with the splines turned out. The end of the arm was a slip shaft spline which slid into the turned out receiver. The forward bushing allows the axle to more up and down with the pinion still oriented to the tcase output. The slip allows the arm to twist, which in turn allows the axle to articulate without bind. Seems in this design that the only bind would be from not allowing the pinion to move up and down with spring arch/dearch.

One other suggestion made by mj was that the spring bushings on the axle should have the bolts vertical to the ground so that there is no bind when the axle needs to shift a bit side to side in articulation (as it wants to do with leafs).

Originally posted by doctor_G
I'm assuming that you have the bar mounted just outside the housing. (close to center as possible)
I was figuring on a two part shackle with mine, similar in design as what H8Monday did with his.
So as much as I hate to say it..................
Maybe try a search under his name. He posted up pictures of it a while back.
I can't see how a modified slip yoke can help you, but a shackle set up that put's you in mind of a revolver shackle might.
Good luck.

I've seen H8's shackle and unless he changed it, its just a shackle that pivots in both planes, its length doesn't change. I don't see how his shackle would help binding at all. He doesn't use a rod end or similar up front so he gets his side to side movement in the jointed shackle. My front mount was a standard shackle and a rod end... The twist is fine.

All the single bar systems rely, heavily, on the spring as part of the anti-wrap system. They will allow spring wrap, all you have to do is over come the resistance of the spring. That said, having a single bar set up is a lot better then no anti-wrap bar. Stiffer springs rates would do better with these setups.

I am just concerned about the amount of bind and spring windup under full droop.

All the single bar systems rely, heavily, on the spring as part of the anti-wrap system. They will allow spring wrap

sure they will, no secret there but they do a good job to eliminate the hop and wrap normally.
i think most of this bind is caused by the spring pin location. an offset pin determines how much a pinion moves by how offest it is. i think no matter what style wrap bar one uses you will get bind if your pin is offset.
that said i think a ladder bar style will work best for offset pins if the length equals what the pinion wants to do and i think any style wrap bar EXCEPT the ladder bar style works well with centered spring pins. so i guess my previous reply was based more on your having centered pins, which, now as i think about it you probly dont.
i think your best bet might be to figure out how long a wrap bar you need based on how the pinion tilts at comp/droop. it may need to be the same a D shaft, or it may be longer/shorter. oh and keep in mind, if you have reversed your spring like some do to improve deprture angle and stretch w/b, your pretty much screwed unless you make the wrap bar attach backward at the bumper.

I have thought about this too....ways to make the springs live longer (no binding) and stop wheel hop.

I am thinking about "floating" the spring perches....weld perches to steel bushings and weld thrust flanges for the bushings to the housing to control side to side movement.....and then use a central ladder bar to control axle torque. The perches would still be located to the springs by pins.

The springs would only be used to support the vehicle and locate side to side. The would not be forced into S shape when one side articulates. The springs (and axle housing) should live a whole lot longer.

But I have concerns that one ladder bar can handle the abuse.

Any thoughts.

Flipper(what's up with the name, dude?) has a good idea that I was pondering before I said "phuc it" and ran coils. The spring bind issue is similar to the Ford radius arm issue. The axle HAS to twist, or roll actually, during articulation. The pinion moves up and down. The traction bar is, ironically, designed to prevent that. Kind of a Catch 22. I got into a discussion with a guy about this awhile back. My suggestion to him was to pull the bolt in his shackle mount at the frame and drive up an RTI or something of that sort, then try to put the bolt back in. It'll make you worry! Worse scenario than that is, pull the same bolt, then jack up the rear of the rig with a Hi-Lift. Yikes!

instead of fixed links go back to hte horizontal shoc thing of hte past..

BUT drill it out and melt stp in the hole of experiment with defferent oils...

I am thinking about "floating" the spring perches....weld perches to steel bushings and weld thrust flanges for the bushings to the housing to control side to side movement.....and then use a central ladder bar to control axle torque. The perches would still be located to the springs by pins.

the reason you run leafs is to keep it simple. what you are talking about doing is just as involved as building a 4 link. :confused: i've seen the floater you talk about on drag cars with 4 links that have to run leafs in class racing. the traction bar would have to be burly(maybe 2 of them) to not keep ripping off. believe it or not leafs do control quite a bit of wrap.

i just think you guys are worrying about losing a drop of water out of a 1000 gallon bucket. :p

i mounted my ladder bar on a slider instead of a shackle. the bolt rides on bearings. easy to mount versus a shackle and allows the axle to move forward to back. it works really well. no wrap.

Originally posted by Robotoy
i mounted my ladder bar on a slider instead of a shackle. the bolt rides on bearings. easy to mount versus a shackle and allows the axle to move forward to back. it works really well. no wrap.

Pics? Shackles allow for forward and back travel... its the 4-5" of down travel at full droop that I am having an issue with.

(I hear you Fullsize... probably will just fab it up, then show just how bad the wind up is when unloaded.)

Originally posted by FULLSIZE


i've seen the floater you talk about on drag cars with 4 links that have to run leafs in class racing.

:p

Drag race floaters typically float front to back (slotted spring plate). The type I am talkink about is rotational around the housing.

Suzukis that flex have this nasty habit of twisting axle housings and ripping off spring perches as well as S-shaping the springs.

Originally posted by twistedmetal
Flipper(what's up with the name, dude?)

I earned it. I was playing on a buggy hill (over 45 degrees) and f'ed up. The truck made a sudden 90 degree turn, climbed the wall of the trail and then gravity took over. two rolls sideways, then the front end hit a tree, spun me back into the trail, and then it did two complete back flips.

Originally posted by FULLSIZE

i just think you guys are worrying about losing a drop of water out of a 1000 gallon bucket. :p
I know that "drop of water" dropped me from first to fourth in the last ERoCC event. Yeah, springs do a little to prevent axle wrap, but they don't do enough.

rkcrawl, the picture you show is kinda like what I was going to build for mine. The two connections at the axle end would have a set of spring bushing and the other point would have a heim joint to allow up and down movement. Plus the slip in the link would allow the axle to move forward, back and twist but not rotate around the axle centerline. I don't see how that could limit the travel enough to be a problem.

Originally posted by snobrder

I know that "drop of water" dropped me from first to fourth in the last ERoCC event. Yeah, springs do a little to prevent axle wrap, but they don't do enough.

rkcrawl, the picture you show is kinda like what I was going to build for mine. The two connections at the axle end would have a set of spring bushing and the other point would have a heim joint to allow up and down movement. Plus the slip in the link would allow the axle to move forward, back and twist but not rotate around the axle centerline. I don't see how that could limit the travel enough to be a problem.

We are mostly on the same page. With the waggy springs and its offset pin, the axle is acutally rotating (ever so slightly) as it droops. So the front of the bar moves down almost 5". I am just really having a hard time seeing how I can accomodate that much movement with out binding/winding up the springs.

I know SpaceGhost is running his yota springs flipped and using a typical ladder bar setup.. I'm guessing I need just need to make it work... I can always try a single bar setup if I need too, just not sold on them.

That "drop of water" counts for a lot.

Originally posted by Robotoy
i mounted my ladder bar on a slider instead of a shackle. the bolt rides on bearings. easy to mount versus a shackle and allows the axle to move forward to back. it works really well. no wrap.

Sounds like a very good solution. As the axle drops the bar swings down and slides back the necessary distance. Somebody posted some spring hangers on here a couple weeks ago that had a bolt sliding on bearings. Using something like that for the mount would definitely save a lot of fab work
http://www.speedwaymotors.com/eCCStoreFront/smi/product_images//Full/91043302_1.jpg

Originally posted by rkcrawl


We are mostly on the same page. With the waggy springs and its offset pin, the axle is acutally rotating (ever so slightly) as it droops. So the front of the bar moves down almost 5". I am just really having a hard time seeing how I can accomodate that much movement with out binding/winding up the springs.


If you shorten the wrap bar then the arc will have a shorter radius and the front will move less. Combine that with about 1" vertical pre-load on the bar (I've heard many recommend this) and poly bushings (instead of heims) on the axle mount and I think you'll be fine. Between the bushings, pre-load, and a inch or two shorter on the bar (if inclined), you should be fine.

*edit* You can also add a cheap limit strap off the diff if you are overly concerned how much the front moves on the bar. Limit the overall droop, limit the bar movement up front, don't affect flex.

I dont know if any of you guys have seen the way mine will twist up. Waggy's with tight clamps and a T-Bar like H8's. (wonder where he got the idea:flipoff2: ). Run a long bar with a longer goofy shackle and decent bushings. There will be plenty of movement in the shackle and enough play in the bushings to let the axle move wherever it wants to. Couple of things to be sure of....Make the bar beefy. Bring the front of the bars to the same point to make a ">", to a "Y", and make sure the rosette welds on the axle are in good shape. You could even have Welderboy shoot some stick in the spreader holes(speaking from experience here). I spun the tube on my D60:( Little bolst at the mount points on the housing wont get it, mine bends 9/16" bolts like spagetti. The single bar over the axle is :rainbow: IMHO, but the do keep you from bending main leafs. I too am with Fullsize, you guys are talking about a minute fraction of binding. As for Snobrdr, the slip will break unless it is grossly overbuilt. Plus the forces with a ladder bar style are vertical, not forward and aft.

Originally posted by Keith
I dont know if any of you guys have seen the way mine will twist up.

Keith - By goofy shackle do mean shackle up or down or are you refering to a jointed shackle? My mount is made and welded up already it isn't coming back off, so I can't do bushing on the axle end. I can, however, do whatever on the front end. The old bar had a rod end to a standard shackle, with a cj spring bushing on the other end. I think it allowed enough play. I take it you don't worry about winding the springs up if you completely unload the axle?

Pix of your setup might help. Guess I'll be wokring up the length and getting some tubing to finish fabbinf this thing.

Thx

Jim

I'm gay, I dont have a digi cam, and I'm too cheap to get the red star. Yep, a jointed shackle, but a study rod end with a standard shackle will do fine. I run the bar above the shackle. I used a goofy shackle because I did not trust a rod end, seen a few of them bust. Some 2" x 3/8" piece of flat stock, some 1" DOM, and some bushings were a lot cheaper than a good rod end. I get just as much travel with or without the T-Bar installed. And no, I dont worry about winding the springs up, I dont notice anything other than my leaf springs dont get beat to crap anymore.

Thanks. I found a a pic of H8s shackle. I can see where it could actually be better then a rod end/shackle.

When I say slip, I don't mean a slip yoke, I mean two sections of tube. One small enough to slip into the other and both overlapping about a foot. The one on the axle end is connected in a "Y" shape. This creates a triagulated bar coming off the axle tube. This bar slides inside or over the other piece. When the axle tries to wrap, it will have to move the bar vertically, but since it is inside of another piece, it can't. But it can twist the bars separately since they are not solid. I mocked up one of these by cutting a YJ track bar in half and finding a piece of roll cage tubing that it would just fit into. Just never had a chance to put it on and try it. The for and aft movement I'm looking at is only to allow the springs to change their length during cycle with out interference.

It may work, but sounds over engineered. Roll cage tubing and YJ track bars are going to bend like pretzels. You will have to make it super duper beefy. With the front of my bar disco'd, I can move it side to side several inches. I think the bushing at the rear have plenty of flex to allow for axle movement.

I was having similer problems..... and right now don't havea wrap bar because my new spring pack HELPS but don't fix it...

What i did... i found the arc of my springs by measuring from a few different points of the axle to differnt solid points on the frame near your shackle mouting location. Then measured at droop, compresson and normal. Then with a rather large piece of Graph paper scetched everything as best I could to Scale.... and tried to be as precise as possible... Then from that you can create the point in space in which there is no need for a shackle and get as close to that point as possible....

with my old leaf pack this point was WAY too low for me so I got a new leaf pack and havn't tried to locate that point with the new leaf pack

also the old leaf pack had a 5.5" block the new one has a 3" block and sits at same height

try that to give you some more information

Originally posted by rkcrawl
Thanks. I found a a pic of H8s shackle. I can see where it could actually be better then a rod end/shackle.

where is the pic of H8's shackle at ?

and where do you guys have the mounting point at on the
axle ? I'm guessing the drivers side tube just off the pumpkin ...

- jack

Originally posted by morpheus


where is the pic of H8's shackle at ?

and where do you guys have the mounting point at on the
axle ? I'm guessing the drivers side tube just off the pumpkin ...

- jack

Passenger's side is better, if it can be made to fit there. That way it counteracts the natural tendency of the body/frame to torque to the right under power.

Originally posted by morpheus


where is the pic of H8's shackle at ?

and where do you guys have the mounting point at on the
axle ? I'm guessing the drivers side tube just off the pumpkin ...

- jack

Mine is mounted on the passenger side, as close to the pig as I can get it. I have a Ford 9" so its not on the tube, but the center section. Here is H8's shackle.

Mine is mounted on the passenger side, as close to the pig as I can get it. I have a Ford 9" so its not on the tube, but the center section. Here is H8's shackle.

thanks. as they say, a picture is worth a thousand words.

- jack