Outer Limits 4x4 Board

Need to bight the bullet and install a torrque bar. Was wondering if anyone on here makes one for a sierra?

Seach 'wrap and twist' or 'slip and twist' and make it youself

While your at it can you knock two up me

Or look at this thread
http://www.outerlimits4x4.com/phpBB2/vi ... slip+twist

hehe.. thanks for the input...

yeah the sky jacker torque bar looks good, but will cost about AU $480 all up.

dont have the time to fab one up myself.

was just wondering if anyone makes one on here or will make one for a cheaper price??

Dan..

Hi there all, I made the other day an anti-wrap bar for my Zuki.
I used
2 x 80 series rear arms & 1 x nut and bolt
1 old Sierra shackle & rubbers
50 x 25 square tube
50 x 10 flat bar
pipe for the shackle
3 high tensile nuts and bolts
I went to One Steel and got some 50 x 75 square ( off cuts $0 )
I bought a 24mm X 60mm High tensile bolt with 2 nuts ($7 at Cedray)
I bought 1x 80 series nut and bolt from a wrecker ( $5 )
And this is what I made
(It is not finished yet as I ran out of gas on my mig!)
It seems to work ok so far!

danman. - have a look at the Trailtough bonz-eye springs - these are designed to counter axlewrap in SPOA applications. it wouldn't take much coin to gat a springmakes to make you some reverse eye springs with a military wrap second leaf that should do the job. (assuming you are SPOA?)

but onto track bars - I have had some interesting conversations with an engineer about track bars.

Basically, this engineer, (and I know they are all different) basically would not accept a track bar unless we could prove that it didn't influence the springs at all.

I tried to convince him the the "sam's offroad" style (as built by bad7oy) was the best possible design and he just asked that we sketch it out based on the measurements of our springs and the travel range we were looking for. they don't work if you do this - they load the springs quite heavily if they are made to suit a SWB sierra.

Other engineers have passed the sam's offroad style on SPUA cars, but the example I am thinking of was a LWB with a SPUA and a very long arm, so the influence on the springs would have been small.

Anyway, we worked and worked on it and managed to come up with a location for a single bar that only "forced" the springs about 3mm through their full travel... but we have never built the bar because with the setup that we are running axelwrap hasn't been an issue, which is OME HD leaves with the overloads removed, 2" bumpstop spacers, N76 shocks and SPUA, however, another factor is that particular car is auto, but I have set up manual cars with the same setup and they don't wrap excessively either. (both cars run 35's or bigger)



You can see the mount we made for the single bar that the engineer was happy with in the photo - it is a long way forwards and lower than a mount off the crossmember. This was the optimal position to work with the springs. The diff end mount was centered above the axletube and was welded in over approximately 40% of the diameter of the tube.

Basically, as Blueridgerunner pointed out in the link posted above, spring rate will cure axlewrap, and the housings don't like the force generated by track bars.

One of the other ways of reducing axle wrap is to properly bumpstop the suspension. If the car settles onto a bumpstop it is much less likely to start the bounce that leads to excessive axlewrap.

Other comments- the chassis crossmember that the body mounts are on is not strong enough to take a track bar, they break. Rod at total 4WD found this years ago with the "rodified" suzuki.

If a Sam's offroad style bar is run, it is preferable to have the shackle in tension under power ( i.e fixed at the bottom with the arm mounting above rather than hanging) as the diff is trying to pull the arm up. There is a risk with a hanging shackle and a steep arm angle than the shackle could invert, bending the springs if a big bounce got going.

Just some comments from my experience.

Steve.

Hi there all,
thanks Gwagensteve for the helpful comments
will took at a stronger crossmember brace and stoppers so the shackle can not invert.

can you tell me more about these bonz-eye springs?

sounds interesting.. cause i need new springs as well.
how well do they flex up??

and yes SPOA..

P.s Love the work on the trac bar youve made bad70y..

looking good mate.. be interested to see how it goes..

www.trailtough.com - they are designed for minimum height and the best axle control.

One of the problems with SPOA is that it needs a higher spring rate than stock to control the axle wrap that SPOA causes, but a lower ride height than stiffer "lift" springs provide or else the car ends up too tall.

My guess is that with some spring made up like these you could avoid a track bar altogether.

Steve.

just been looking at the website now..

wondering if i could get these instead of a trac bar...

the only thing is that my car is bloody high enough as it is and it says these springs provide 2 inches of lift..

but on the up side, they look to be the same price as a trac bar, therefore ill be killing two birds with one stone..

might ask if they make them standard height.

Ive bit the bullet and ordered a sky jacker torque bar from low range.

everyone who i have spoken to thinks that springs that combat axle wrap will dramatically reduce flex. which i agree.

least this way i can run heaps flexy springs.

will let you know how the bar is when i get it in.

Dan

Some ideas Ive been toying with, way back in the old days, Rick Pewe'
ran a kind of military wrap with the second wraping around the front eye and back to the centre pin to fight axle wrap without killing travel.
Or I saw on pirate recently someone using wire cable from above the spring top plate forward to above the front spring eye apparently it works very well.
Nik

The geometry changes with leaf springs are really very difficult
to get around. The old fashioned 'Traction bars" under the leaves as loved by the GTHO's etc were perhaps the simplestsolution to a complex
problem - but useless for off roading.

Tried lots of schemes many years ago with a repowered LJ but none
really worked and some make things lots worse.

I wonder if anyone has tried reversing the old traction bars to on top
of the axle facing backwards ? theory says it should work at least as
well as underneath even if its harder to do.

MightyMouse wrote:The geometry changes with leaf springs are really very difficult
to get around.

We actually used a card and a pen as a marker and plotted a trace of the axle movement on Greg's car. It was a complete mindscrew, and that was with quite limited travel.

MightyMouse wrote: The old fashioned 'Traction bars" under the leaves as loved by the GTHO's etc were perhaps the simplestsolution to a complex
problem - but useless for off roading.

Tried lots of schemes many years ago with a repowered LJ but none
really worked and some make things lots worse.

I wonder if anyone has tried reversing the old traction bars to on top
of the axle facing backwards ? theory says it should work at least as
well as underneath even if its harder to do.

I like the idea, especially on a car with flat springs already (SPOA) but fundamentally we found that the ideas for controlling wrap get more and more and more complicated until it is easier to just build a coil car. My guess is that if your idea gave enough clearance to allow full droop it would allow excessive wrap at compression.

To me, most of the issue is guys trying to run too little spring rate and expecting too much travel. vertical travel at the centre of the diff could be restricted to 4 or 6 inches (easier to make a bar work for) and still have unrestricted articulation. The problem comes when you try to build a car with 79" of WB and for 10" of vertical travel at the bar. It will never work properly because one way or the other the springs are being massively overarched which will cause big geometry changes through the travel which the bar can't properly accommodate.

Sierra rear springs are only designed for 6" of travel. that's not a material or spring design choice, it is a function of their length. Once you can reach your bumpstop, less spring rate is just going to cause wrap. Pulling leaves out of a SPOA to lower it (flat springs) doesn't allow enough rate to locate the axle properly.

I like the idea of a bar that doesn't do anything until the car needs it - think about it - a traction bar doesn't have to do anything when the suspension is in droop because the car doesn't ave any traction, so a bar that sits loose (or a cable) can work because it only goes tight when the suspension is in a position that the car can develop traction in, which can only be ride height or into compression, never into droop.

I think lots of bars put more force into the car by trying to fight droop than they ever do in fighting axlewrap.

Just some thoughts.

Steve.

Yep - a bit more thought does show issues of spring curvature could
make it a problem for a top / rear facing traction bar setup.

Might put it on my todo list just before the anti gravity hill climbing system.

It think axle wrap is just going to be with those of us who have simple
leaf sprung rears. Perhaps decouple the spring from the axle .......

Spring wrap sucks
As I have some much other stuff to fix/do/improve I have h/d ome dakar rears at the moment complete with overload leaves. I still get ok travel down and a little up but the massive overloads help stop wrap, plus when it starts to wrap I back off or take another line so these springs are holding up pretty good.
The thread on pirate about using wire cable was a good read. Its cheap and easy to try and it was like Steve was saying it only stopped wrap it didnt affect anything else. It have to see it work to know for sure though.
i just checked out trail toughs springs thats what I was saying Rick Pewe' ran on his flatfender years ago, $240 us a pair plus frieght I might see what it would cost to get something similar done to mine.
Nik

Twin shackles and tri 4-link. .
But damn you would have to love your leaf's to go this way instead of just 4-link with coils/air shocks.

Layto....

I spoke to a spring builder and they said about $500 to build springs similar to the trail tough springs. Is there a Oz supplier of tt stuff or is it better to go direct?
Just tossing up ideas, the spring builder that "specialises" in 4x4s also said that my straight up and down rear shackles are the correct angle and my idea of having them more like 45o to the chassis was wrong?
Nik

NIK wrote:I spoke to a spring builder and they said about $500 to build springs similar to the trail tough springs. Is there a Oz supplier of tt stuff or is it better to go direct?
Just tossing up ideas, the spring builder that "specialises" in 4x4s also said that my straight up and down rear shackles are the correct angle and my idea of having them more like 45o to the chassis was wrong?
Nik

He's probably right in that a vertical shackle will minimise spring wrap.... and minimise travel. a steeply angled rear shackle will soften intial rate, kinda like reducing antisquat. Shackle angle is related to how much comopression and droop you have in the suspension. the more compression your setup allows, the more vertical angle on the shackle.

ith bumpstop spacers, I setup the shackle to basically go to maximum premissable angle at full compression, but I can't comment on your application.

there's no TT agent in aus that I am aware of.

Cables are an interesting idea, might be worth a longer look.

MightyMouse wrote:Cables are an interesting idea, might be worth a longer look.

For those interested
http://www.pirate4x4.com/forum/showthread.php?t=335637



I might give this ago

Anybody seen Caltracs, the drag guys have heaps of success with them
Only problem is the mount spring under so affect ground clearance
Would the same thing work over the top of the spring

http://www.calvertracing.com/info/info.htm

Don't think it would work up the other way - the force is working in the wrong direction.

As Layto points out - I 4 link and double shackles is the only real way of separating drive force and spring rate, but then what medium is used for springing is irrelevant- it's not about leaves anymore.

Steve.

I forgot to say the $500 was only for 2 mains, 2seconds and 2 1/2 leaves to stop wrap I had to use the rest of my pack, so thinking $240us for a pair of springs tuned for the specific purpose might be a better option.
Steve can you give me a quick rundown on "squat" I dont think I got it last time.

Yes that was the thread with the cable anti wrap set up.
Nik

Yep it suks ,had it once pretzled a rear shaft , pity i cant find the old pics , i built a pair of traction bars and they fixed it .

most semis have a tration bar setup , the cable is used by mecedes if im correct off course it a bit bigger then the one above

The thing is with the cable is your controlling in one direction , hit reverse
in a high traction spot and bummer .

NIK wrote: Steve can you give me a quick rundown on "squat" I dont think I got it last time.

Squat/antisquat is talked about constantly in relation to link suspensions but almost never in relation to leaves.

Basically, "squat" relates to the the amount or ease the that back of the car compresses and the nose lifts under acceleration.

with a link suspension, excessive squat results in the nose going skyward and excessive weight transfer on climbs, so the % antisquat has a big effect.

On a leaf car, the effect is much smaller, but in a car with a vertical shackle, the initial first bit of travel will have a very high rate because the shackle doesn't really want to start moving backwards to start with. Momentarily, the suspension kind of locks up.

if you move the shackle onto a greater angle, the force acting on the shackle can make it move very freely, so the back end sits down and the car "bites" and "hooks up" better.

If you can set the suspension up with very limited compression travel, bascially, you can make the car sit very close to the bumpstops when climbing, so that the squat under power makes the rear of the car settle onto the bumpstops, which makes the car put power down in a very predictable way.

I am passionate about the behaviour of cars with limited compression travel, low roll stiffness in the front and high roll stiffness in the rear. (and some squat) This is the exact opposite of the way that high performance cars (winch challenge, OBC, rock racing) are setup, but I don't hit stuff as hard as they do and prefer the predictability when creeping around.

Steve.

Ok im using a lap top , see if some one can draw it better for me ,and i could tell you what its supose to be .



it will reduce your up travel and it includes the bumpstop wich is a standard front seirra unit ,

I used these for a few years on standard springs with a few leaves removed it cured the prob , bar was made from thick walled tube
a large threaded peice welded in the end , and using some shackle rubberes on each side of the channel made it adjustable for tension , we used to lossen them up for bog hole comps this was apart of my engineered spring over .

sorry my paint draw skills a crap .

You're right Dozoor, your paint skills are crap

If you start with a SPOA with flat springs, that should work fairly well I think.

It's not really an option for an arched spring (or a SPUA) that has to flatten a fair bit as it compresses though as it will really start to pull the pinion down.

I like it though.

Steve.