Radius rods on the rear, open drive conversion ..Lets argue

[Roothawg]

I read something that I found interesting in this months Street Rodder magazine.

Now I could care less what you think about the magazine, what a Rat Rod is or your interpretation thereof. I just found this article intriguing and want to make sure if what he is preaching is valid.

In the Shop Manual section, Ron Ceridono states that running rear 36 radius rods on an open driveline as a primary means of locating the rearend is unsafe.

Now, he says that some reinforcing and additional links are needed to be safe. Just wondering what your take is on this? I had thought about this very conversion on my 36.
Engineers? Rocket Scientist, Hamb Metallurgist?????

Just in case ya wanna read it....Aug 2004, pg 203-204. http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Unkl Ian]

If the bones are split to the outside of the frame rails,
what is the difference between split bones and ladder bars?
You can get away with it with an I-beam,but not on the rear.

If they still taper in towards the center,like the P&J set up,they should be ok.

The further apart the attatching points at the front,the more they will work like ladder bars.

There was a guy here a few months ago,with a set of Yellow '36 split bones.
Very broken. http://www.jalopyjournal.com/ubbthreads/images/graemlins/shocked.gif Luckily for him,he found it before it found him.

[34Fordtk]

I am going to split my 40 bones,are the much different than 36's?? Is there much difference in just opening them up a little or all the way out to the frame?? http://www.jalopyjournal.com/ubbthreads/images/graemlins/tongue.gif

[Roothawg]

Keep in mind guys this is the rear...not the front bones.
The 36 bones are sought after because the "unbolt" and have the transverse leaf that retains the traditional look but on an open drive.

Here's what he says in his article:

"Truth is, those rear radius rods were actually rather flimsy and only served to stabilize the outer ends of the of the axle housing; it was the torque tube that located the rear end and took all the abuse of traction and braking forces. So, even though it has been done, I don't trust early Ford wihbones as the only means oflocating a rear end."

[four-thirteen]

you can split the bones on an i-beam axle without problems, because an i-beam will twist without breaking. you can split the bones on a rear end, but you WILL break stuff.

take a paperclip, unbend two of the legs so it looks like a U shape. lay it on a table. hold the two ends down to the table, like they were mounted to the frame. now pick up one corner of the U. the other cprner comes up with it. if you want that corner to stay flat on the table, something has to bend or break.

crawl under a car with a poorly set up rear suspenion like split bones or ladder bars. a good number of them have parts that have been rewelded because they broke. and you can bet they ride like a lawn tractor, because the rear end can't act indendently. David

[DrJ]

[ QUOTE ]
Keep in mind guys this is the rear...not the front bones.
The 36 bones are sought after because the "unbolt" and have the transverse leaf that retains the traditional look but on an open drive.

Here's what he says in his article:

"Truth is, those rear radius rods were actually rather flimsy and only served to stabilize the outer ends of the of the axle housing; it was the torque tube that located the rear end and took all the abuse of traction and braking forces. So, even though it has been done, I don't trust early Ford wihbones as the only means oflocating a rear end."

[/ QUOTE ]

Henry Ford was a stingy,cheap SOB.
If he thought he could get away with building a '36 Ford without the torque tube and just run them cheap-ass little radius rod/wishbones, don't ya think he would have done it in the first place? http://www.jalopyjournal.com/ubbthreads/images/graemlins/shocked.gif

Ron is right, and if you don't know of him or trust his credentials, then read all the stuff he wrote in the pages Tex Smith's Hot Rod Mechanix magazines.

[choprods]

Ill let ya know...... http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Psychobilly Boi]

Hey Guys,

I'm running 42 bones on the rear of mine - unsplit with an open drive diff. what do you need to do to stop the mounts from cracking or fix the radius rods with wishbone issue?

Someone suggested running a rod above the drive shaft to a mounting point above the wishbone mounting point... explaining that this will stop the back/forward motion of the diff under braking and acceleration which in turn stops the mounts from cracking.

What do you think?

Danny

[Roothawg]

[/ QUOTE ]Henry Ford was a stingy,cheap SOB.
If he thought he could get away with building a '36 Ford without the torque tube and just run them cheap-ass little radius rod/wishbones, don't ya think he would have done it in the first place? http://www.jalopyjournal.com/ubbthreads/images/graemlins/shocked.gif

Ron is right, and if you don't know of him or trust his credentials, then read all the stuff he wrote in the pages Tex Smith's Hot Rod Mechanix magazines.

[/ QUOTE ]

I don't know Ron or even care how wonderful he may be.
I just want to know if this is true? Are we setting ourselves up for failure? I don't want to put my ride at stake...but I do like the looks of rear bones. I just want to be safe.

[DrJ]

If I was running them on an open axle and anyy kind of torque motor at all I'd also run a 80's Camaro style torque arm to take the place of the missing torque tube.

[Unkl Ian]

[ QUOTE ]
If I was running them on an open axle and anyy kind of torque motor at all I'd also run a 80's Camaro style torque arm to take the place of the missing torque tube.

[/ QUOTE ]

And change the mounts,on the rear of the bones,so they act as trailing arms.
You only need one torque arm,not 3.

[Roothawg]

So would that be a 4 link?
Or would that be 2 triangulated 2 links inside of one another?

What if you have a set of bones, split but not all the way to the framerails.....and a panhard bar? The tranverse leaf and factory crossmember will handle some of the torque, won't they?

[Jugghead]

l have also been informed of this type of failure as l am installing 36 bones in my car.
l have also been told that to get around it you run a torque to compensate for the missing drive shaft as said before, also to install a plate where the casting meets the tube to make that area stronger, thats where the weekness is.

[choprods]

I may be in error- but I feel like my set up will work.
It will however have very little torsion capability I know.
I hate the way an early ford set up rocks side to side so excessively.
Mine only has 1-1/2" total travel in the vertical mode.
I ,like Roothawg think the rear spring heavy Truck gas shocks etc will behave better by NOT allowing much 'twist" right to left before bottoming the housing to the frame.
I am adding snubbers there.
a common form of ladder bar failure occours as a result of the rod ends having a small diam threaded end and running a JAM NUT there to totally prohibit the ladder from pivoting the limited amout it could -THEREFORE allowing the bar to twist itself into failure at that joint area.
Mine have coarse threads 1-1/4" diam and are not locked where they thread into radius rod allowing that small additional amount of give as well as the forged 3/4" bore heims joint coupling the frame to the radius rod ends.

[Unkl Ian]

If you had one trailing arm easch side,a torque arm like on the latemodel Camaros('84 up),
with a panhard bar,that all you need.The trailing arms locate the axle front to back,and the torque arm handles the reactions in acceleration and braking.Aside from the spring(s)and sway bar,the rear suspension is free to move in roll.There is no bind.

If you wanted to get away from the panhard,you could go with a pair of triangulated upper trailing arms,to creat a triangulated 4 bar.Again,no binding.



[ QUOTE ]
The tranverse leaf and factory crossmember will handle some of the torque, won't they?




[/ QUOTE ]

Probably a negligable amount,the spring can actually twist a little

[Roothawg]

I am not totally sold on the setup. I just want to weigh out all my options up front, before I spend a bunch of money only to fail. I have a set of 36 bones but should I use em?

[DrJ]

All the torque that makes cars with enough torque want to do wheel stands is transferred to the weight of the car through that lever, the torque tube/lever/arm. Is that '36 radius rod strong enough to hang the whole car on the end of? I doubt it..
Is that picture clear enough?..
(just trying to help, not feeling argumentive at all tonight, it's too hot and humid...) http://www.jalopyjournal.com/ubbthreads/images/graemlins/blush.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

All the radius rods were designed to do was triangulate the axle tubes into an unflexing structure to keep the rear axle perpendicular to the torque tube and reduce the possibility of stress fractures.
Ya see, the banjo,being round in the side view is strong enough to take the torque wraping up of the engines power, but as one wheel pushes forward, as it does, it's torque would be pulling on just the bolts that hold the axle housings onto the banjo but the wishbone, as installed originaly keep the tension and compression forces on the torque tube instead of the Banjo housing bolts and bolt holes.

A torque arm would work just like a T-tube, in that it would swing the rear endthrough an arc like the Torque tube does, definitely different from what 4 bars do.
or
What Ian sid too if you're not running a Ford Banjo.

[Roothawg]

I guess you are right about the banjo being designed differently........I hadn't thought about that.
I may stick with what I know, even if it is "cookie cutter".

[cornfieldrodder]

I went through the whole 36 vs 41 (in my case) radius arm idea. The radius arms, pivoted at both ends, with a torque arm parralell to the driveshaft was the only situation that I would take my kids along with. Since I am going too damn low, have the driveshaft way above the floor level, which is welded to the bottom of my rails, the torque arm would hit no part of my chassis, but slam into me occasoinally. Then I looked at some more of Harry Miller's wonderful creations. Now I'm going with four 1/4 eliptic springs set up as a 4 link on the rear. Henry's bones just weren't designed for how we rodders use them. http://www.jalopyjournal.com/ubbthreads/images/graemlins/frown.gif Enough of my rambling on the subject.

[Tman]

Bones dont have the strength w/o the TorqueTube. I did the bushed ends and Tork-arm.

[disastron13]

Choprods, something about that doesn't seem right to me. If you put your heavy duty rod end in a big vise and had a couple of your extra-large buddies reef on the other end of the radius rod, would it hold?
I don't get how leaving off the jam nut would affect the strength of the joint, either.
How do you figure?

[Tman]

One of the Texas? HAMBers folded a couple sets of split bones on a coupe a few years back if I remember?

[Hackerbilt]

DrJ covered it well in my opinion.

You have to remember we are dealing with TWO potential failure issues here.
(1) Failure caused by binding as fully split bones try to flex while the car leans in a turn or enters an angled driveway etc.
(2) Failure caused by the bones being unable to absorb the rotational twist caused by torque loading as the car accelerates OR brakes hard on LEVEL ground.

BOTH issues can be addressed individually so make sure your setup prevents BOTH problems!!!

I REALLY like 36 style bones...I'd run them, but I'd do like the Dr says and add something to absorb torque AND run them as close together as possible at the forward pivot point as well.

The bones that bolt to the axle end with the backing plate bolts are NOT acceptable as the ONLY axle location device no matter how you configure them IMHO. The outer forged end is just too weak and the tube thickness just isn't there either. I'd only use them if I cut the forging off and added a bushing to the rear so they could be used as lower links in a multi-link suspension.
I did see an added upper link somewhere that joined the center of the axle housing to the front of the narrowly split bones to form a ladder bar like truss...seems workable in a lower power situation. Both failure problems are addressed...but I still don't like the questionable forged ends on the later bones!

IF something breaks, I want it to be a total surprise! If I expected it might break and built it anyway...?

Well, that means I FAILED doesn't it?

4-1/4 elliptics would ride and work nice but could have some lower spring wrap problems under acceleration with a strong motor. I'd bias the leafs to favor the lower packs slightly...maybe even do a "Military Wrap" on all the mains.
The idea seems very workable. Seems unsprung weight would be very low as well.

Double cantilever suspensions (uses FULL 1/2 elliptic springs but mounted in a 1/4 elliptic fashion) are similar and were used on several large 1920's luxury automobiles and were even on 30's race cars like John Cobb's W12 aircraft engined Napier-Railton!
In other words...I think torque issues CAN be addressed! http://www.jalopyjournal.com/ubbthreads/images/graemlins/smirk.gif

Bill

[Rocky]

Some guys have gotten away with it but I wouldn't trust the bones to handle much torque in a very heavy car for very long.
T-man is right about one of our Texas bros folding up a very nice pair of ford Bones at the strip one day. He even posted photos of it. I was because of that particular occurance I was planning a torque arm for the Rocky 33 before I put the new, improved flathead in place. The 33 went to T-man and the new flatmotor went to av8 before any torque arms were fab'd up. I was planning on using a length of 2"X3" box tubing and mounting it solidly to the rear axle and bolting the other end to a frame-crossmember with a big squishy bushing from a early 70's chevy pickup traililng arm. A big spherical rod end would also work in place of the squishy rubber bushing.

[thirtytwo]

[ QUOTE ]
I am going to split my 40 bones,are the much different than 36's?? Is there much difference in just opening them up a little or all the way out to the frame?? http://www.jalopyjournal.com/ubbthreads/images/graemlins/tongue.gif

[/ QUOTE ]yes and yes 36s are more substantial than the 40s and do not use that little forgeing to mount the radiusrods unless its a 35-6 end if you split them to the frame it turns the axle into a giant sway bar if you bring them in like pete and jakes bars they are able to piviot, better yet do as samiyam and weld them together unsplit then they can pivot and borrow strength from each other i work on a 40 pick-up done this way that had been a rod since the 60s and pulled a 5th wheel 100k miles on it they still worked fine!

[Roothawg]

Thanks for all the input.As much as I hate to say it....I think I may just bail on the whole idea. I can fabricate something that will be a little safer and easier as well.

[C9]

Why not do what some of the modern rod builders do?
Build a triangulated 4 bar setup.
Similar to the ones with the lower bar directly under the frame.

In your case use the split bones as the lower link, bush it both ends, maybe a nifty bracket/tab setup at the rear to disguise somewhat the fact that it does pivot.

Then a pair of upper bars triangulated so as to locate the rear end or - better yet in my opinion - run the upper bars parallel to the 'split' bones, but on the inside of the frame.
Add a panhard to the mix.
Most times a panhard can be hidden away from the casual observer if you don't like them.
I use em, don't mind their looks and they're hard to see anyway.

What you've gained here is using the split bones loaded in column.
Push-pull in other words and no bending stresses from torque.

With the bones and upper bars parallel, both vertically and horizontally and a panhard in place you'll find it handles pretty well on the street.

Use a transverse spring as well.
It's gonna ride better due to more capability for tuning as well as more travel available than the coilovers.

What will really help here is a sway bar.
There are some nice ones in the aftermarket, but a good one can be found at the wrecking yards.
Don't overlook the foreign cars either, a lot of their stuff is sized just right for our hot rods.

Some trad guys may poo-poo this approach, but to my way of thinking you can have your cake and eat it too.
At least as far as good handling and trad looks go.... http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Flat Ernie]

T-Man,

That pic makes me wonder if everything moves in the same arc - if not, it'll bind & may break.

Of course, it could just be the angle of the pic that makes the arms look different lengths... http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[38Chevy454]

I think there are many good points here. I have actually been going through this exact question for my 27 coupe project with 394 Olds power. Was going to use 36 rear bones, but I think it needs an additional upper link or torque arm like mentioned by several previous posts. So instead of using the 36 rear bones, I am going to use a ladder bar set-up I think. Maybe not the most traditional, but then neither is the Olds rearend in place of the traditional banjo.

Here is the engineering reason that the unsplit bones are not sufficient. Several factors are involved.
1. The bones do not have sufficient stiffness to hold the bending forces of a high torque engine. The stock radius rod is designed to hold the rearend in place as stated, not subject to bending forces. Reason that many rods get away with it is because the skinny bias ply tires spin before any real serious torque bends the radius rods. Get enough traction and a healthy engine and the bones will permanently deform or break.
2. By splitting the bones you create a very stiff sway (really anti-roll) bar with the rearend housing. That is why it is best to leave the bones pointing in towards the center as much as possible. Rubber bushings can be used to take up the distortion so it is not transferred to the welds and mounts.
3. If you use the 36 rods mounted solid to the rearend and split to be parallel with the frame, the upper mount has to be able to change length. It must be exactly the same length as the lowers or it has to be able to change length, due to the different arcs. That is why it was suggested to mount the lower rod using a pivot-able design. The stock 36 rod uses a solid mount. In stock configuration there is not change in arc length of the rod, so it does not require a pivot.

An alternative to the torque arm is the triangulated four link, or even a triangulated upper wishbone that mounts with a single point on the rearend. This would keep from requiring a panhard bar if set up correctly.

The metallurgy of the rods has nothing to do with the problems of splitting them and running open drive. It is a problem of stiffness, and to some extent yield strength. Stock radius rods are low strength and will bend (and potentially break after bending too far). As evidenced by the examples cited.

A stock 36 radius rod would make a fine lower bar as long as it has some additional upper bar or torque arm to handle the rotational forces due to torque.

[Roothawg]

One of the factors I have to consider is the fact that mine is a 36 pickup. Very little weight over the rear end and it tends to ride like a buckboard if the springs are too heavy.

I had looked into running 2 small airbags over the rear end, (up out of sight) and using a parallel leaf setup with 1-2 leaves only. Maybe throw in a couple of trailing arms to help keep it all in line.

Does this sound like something that would be reliable. I am more concerned with ride and adjustibility more so than the typical lowering aspects.

[metalshapes]

Root, did you read "A-bone suspension question" in the Tech O Matic?
You will find some more info there...

[Roothawg]

Actually there are a couple of em in there....I forgot about em.

Thanks I'll read.

[4t64rd]

I was hoping this would come back up again

I never saw the pics of Tman's torq arm setup the first time around, so I thought I'd draw up an idea I had for replacing the structure lost when using an open drive rear end, 2 radius rods on the same pivot point as the radius rods, that way the radius rods are only locating the ends just as Henry did it.

I'm not an engineer, so if anybody sees something that won't work, tell me before I start buying stuff to do this.

[Kevin Lee]

God I'm glad I'm using a torque tube. Hotchkiss is the Devil.

[BigJim394]

When I got my 40 Tudor w/394 Olds and B&M Hydro 30 plus years ago it came with a 58 Chev rear with unsplit 36 Bones.
The Olds was a "full house" engine (12.5-1 Pistons, Wild Cam, Headers, Dual AFBs off the 425HP 409 motor), and the local older rodders suggested getting rid of the 36 Bones and getting a PSI rear end mounting kit that was a heavy duty copy (kind of) of the 36 bones.


So, I did some research in old rod magazines, mostly from the late 50s to very early 60's, and found a few mentions of crashes in drag races where the rear used 36 bones and the torque from the engine broke the weld where the tubular part connects to the rear cast iron part. Some guys died. Henry Ford's engineers did not design these bones or that weld to hold up to big torque. When R&C stopped publishing and they went to the square bound Quarterlies, they did a build up series on I think a 36 Roadster (with an AMC Motor maybe), and they used 36 bones, but they welded gussets to that weak area on the bones. I think Klazurfer once scanned and posted those photos.


I ended up getting one of those PSI kits after a year and a half mail order nightmare. Thay apparently did not sell a lot of them and they have not been available since the early 80's.


In the late 60's/early 70's I saw more than a few guys extend the forks on old Harley Springers by using sections of old ford wishbones, as they were pretty much the same size as the springer tubes. Most of the guys used 36 bones for some reason, although I was told that other years worked fine. Well, some of the bones that those guys cut up had been in a pile of bones at a junkyard for decades, and due to small drilled holes in the bones (probabaly for e-brake cables) sometime water had gotten in, and there was some significant rust inside some of them, and an inspection of the factory welds at the tube/casting mating point, sometimes showed not the greatest weld penetration.

[Johnny Sparkle]

[ QUOTE ]
Mine have coarse threads 1-1/4" diam and are not locked where they thread into radius rod allowing that small additional amount of give as well as the forged 3/4" bore heims joint coupling the frame to the radius rod ends.

[/ QUOTE ]

I would be worried about the threads wearing out and eventually failing this way. We use alot of spherical rod ends at work, and everytime someone forgets to lock one down, it fails. The jam nut prevents the pieces from rocking against one another. Throw in a little sand and dirt from the road on top of loose parts rubbing against each other and you get something that isn't quite safe.

[SamIyam]

I just measured the scrap piece I cut off the '36 bones that I used on the Roach Rod.

The wall thickness is .130

You aren't going to break that.

The "weak" area in question must be the joint where the forged end is butt welded to the tube.

I've been doing a stress test for the past three years on my set... and so far, they've held up just fine. I would go as far as saying that I ABUSE them on a regular basis.

Anyway, if you were really concerned about them... you could weld a little fish plate over the area where they are welded together... effectively making them suitable for 7000rpm launches with slicks.

As far as the other bones go... I couldn't tell you how stout they are... I can only vouch for the '36 bones.

Also DON'T SPLIT THE REAR BONES!

Tie them together with either a Model A front wishbone yoke... or some metal.

Then fasten that to your tranny x member (A dropped tube member works best) via a 3/4" heim joint or original ball in socket set-up.

That way, the whole shootin' match will be triangulated... preventing it from moving side to side and allowing it to rotate about the axis of the ball and socket as each wheel moves up and down.

Sam.

[Tman]

My bones and the Torque Arm are almost eggzactly the same lenght. The travel is quite free, sorry, that pic just makes it look wierd.

[Roothawg]

Sam, what about driveshaft clearance? Is that an issue? I realize the torque tube used to be there but it was also stationary.

[Tman]

Try this one.

http://www.hotrodworks.com/radiusrodmount.htm

[Roothawg]

That looks like a pretty nice piece T. How did you mount your torque arm to the 9"?

[Digger_Dave]

4t64rd, think you just might have a solution if....
The wish bones are NOT SOLIDLY afixed to the axle.

SJ Fast once showed (might be in TECH still) an idea that he used. The outside wishbones are attached to a ring that can rotate on the axle. It would mean either removing and rewelding the bearing ends OR you could split the rings in half (like bearing shells) and weld them on the axle. (just the ring so it can rotate on the axle) To keep the ring/wishbone mount(s) in position, SJ then mounted narrow rings on the axle to keep the "slip/bones mount in location.

This would get rid of the "SWAY BAR" effect, and take the load off the bones mounting point. You could even mount a Zerk fitting on the ring to give it a shot of grease once and a while.

I have seen it done on some oval track racers, even with a banjo rear axle. The axle (straight tube or tapered) would need a bit of machining (very light) to give the captured slip/bone mount ring a smooth surface to ride on.

I think both the front and rear ends of the bars and the front end of the bones will need tierod ends or Heim ends to allow for twist.(in side to side motion)

Nice drawings BTW.

[Digger_Dave]

If you haven't been following THIS thread..
take a look! Has some pictures of interest!

http://www.jalopyjournal.com/ubbthreads/showflat.php?Cat=&Board=UBB1&Number=467568&page=1& view=collapsed&sb=5&o=7&fpart=all

[**DONOTDELETE**]

Here's a quick sketch of what I'll be using on my lakesmod. The torque arm will handle all of the acceleration and/or braking forces. It will also provide a place for a loop to enclose the driveshaft (not shown). The oval tube wishbones, split to the side for a traditional appearance, will serve only to locate the axle fore and aft. Note that they are mounted at the same plane as the axle centerline. That way the forces are going directly down the oval tube centerline and having bushings or swivels at both ends, they encounter no torque forces whatsoever. All connections are in shear also.

There will be a panhard bar and a roll stabilizer too. This design will work with any springs the builder uses. I'll have torsion bars mounted parallel like the sprint cars from the 50's and 60's.

Most people don't see each component by itself. Think of it in those terms and this becomes a simple design.

Any questions ?

[Roothawg]

Thanks Dave. I actually missed that thread somehow. I started reading it the other day and got sidetracked before I got to the good pics.

[cornfieldrodder]

Hacerbill, with only a Quad4 for power, there will only be about 160FT LBs of torque to deal with. That comes in way over 3000rpm. My real concern may be spring wrap, therefore wheel hop on hard braking.
DrJs arrangement looks ideal if one is going to use the old bones split to the outside of the frame. SamIam is right, dont split the bones and the geometries a whole lot better. I still think a torque arm is a good idea, though.
A well designed torque arm cam be below or at the axle centerline too. That can solve some problems for space critical situations.

[Digger_Dave]

Hey SJ, haven't "seen" you around for a while!

Did I explain the drawings you posted "long ago?" I might have explained the setup a bit different.

[roadstar]

The more I read the more I feel this set up has some real issues. The rear axel is gonna twist. There is no question about that. So one end of the suspension needs to pivot. That is why it is recomended to use a rod end with a split bone in the front. SO it would make sence to use the same in the rear.

I'm talking about a OEM style tierod end here with a tapered shaft and nut. Or a hiem that would give with the twist of the suspension.

And I really see a proplem with them the farther you split them with out having some type of mounting that will give with the twist of the suspension.

Just my thoughts.

[34Fordtk]

Ok so I checked out my banjo today,my bones unboltfrom the ends of the axels and are bolted together on the other end.So is this a 36 rear end?? Not the 40 I thought..
Has anyone tried a true 4 link with the stock spring and a panhard bar? Would the spring act like one??

[34Fordtk]

I reply and it drops like a rock............ http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif

[Hackerbilt]

I think your OK with the 4-1/4 elliptics Cornfieldrodder!

The lower springs would be in tension and the uppers would be trying to chatter...but a couple of clamps should cure that.
Hmmm... The real issue might be the actual location of the upper and lower spring eyes in relation to the rear axle centerline. Trying to get the car really low would make it easy to put the upper eyes close to the axle centerline and that would aggrevate the chatter problem as the upper spring would have no leverage advantage over axle twist.
Of course you could always use a center torque arm as well!!!

My initial plan (IF I were building it! http://www.jalopyjournal.com/ubbthreads/images/graemlins/shocked.gif)would see them in vertical alignment with the center of the axle, as equally far apart vertically as possible front and rear and equal distances above and below the axle centerline.

Rollsteer might be an issue as well due to the short working length of the spring packs. I think it would be a good idea to set them up "flat" at ride height, as if they were a short 4 link...which they are really!

I wonder what the actual advantage was for the old racers to use this setup!?!?

Bill

[Andy]

The 37 on radius rods bolted on at the backing plates and bolted together thru a boss under the torque tube. It could be a 40 axle.

[Tman]

Root, no pics up close, but I have a heavy bracket that mounts a Pete AND Jake urethane rod end in double shear between to tabs. It bolts to two of the 3rd member bolts on the left side of the driveshaft. You can see how it works next month.

[Tman]

Root, I have TWO 1600# Airbags that are new if you want to use em for your truck? I have $100 in them but am willing to trade as well.

[Nimrod]

I built a four link using '36 bones as the lower links (mounted outside the rails) and triangulated uper links, stock '32 spring and no panhard bar. The spring alone should be enough to center the rear...thats how it works stock.

[**DONOTDELETE**]

Digger_Dave....you explained it well. That connection to the rear axle is a bit more complicated than my rubber bushing concept but it does work. In fact, I've done that one.

How ya been ? http://www.jalopyjournal.com/ubbthreads/images/graemlins/smile.gif

[Tman]

Here is that bracket Root.

[Roothawg]

Ahhhhh.....nice work. I may be interested in the bags. Bring em to the drags.