My jag rear radius rods

[Keeper]

Okay I guess its time to revisit my radius rod design. It seems that something that should have worked a couple months ago....no longer will. So lets get it all out and over with now....I really hate redesigning/recreating things.

Okay first up lets go over some specs:

87 Jag rear with 2.88 and PL.

Tie bars and main base plate, are 3/8 steel, made by Youngster a couple of years ago.
All the plates, and brackets are also made of 3/8 plate.
Radius rods, tie-in rods, supports, whatever you want to call them today are all made of 1 inch .219 wall DOM tubing.
The uppers/inner rods are 12 inches long mounted at a 60 (actually 59.4) degree angle - heims on the top, clevis on the bottom.
The outers are 37 inches long. - Rod ends on the back side, heims on the front.

Lets go over my thinking/research. I started off with the CCR plans for the jag mounts, upon further research by folks that are putting IRS into everything it was recommended that the outer radius rods intersect the inner pivot points. (Images from UK Hot Rods)

But lets start with the inner mounts, as they will be easier:

I originally had a 3/8 "tab" used as the upper mount.

On the recommendation of Ted and Gerry, I changed it to a double shear mount that should be a lot stronger:

Now the outers:

I designed my trans mount to house the inner mounts as that was the intersection point. With this setup I have run the suspension throughout the full range of movement (with out the springs installed) without any binding. The trans mount is bolted to the cross member with 4 5/8 Grade bolts.

The first version of the mount turned out pretty bulky and ugly so I re-created it.

First version:

I do not seem to have any pics of the current mount.

The rods themselves are again 37 inches long, 1 inch .219 wall DOM tubing. I made that bend to aid in any adjustments if necessary and for a cleaner look, but if it will be a failure point by all means I will make up some new ones, or just gusset the bend with some 1/4 plate. BUT I need some more the "Those thin things you used will break"

The coil over mounts were mounted 26 inches apart to help reduce some of the harshness the 4 coil overs would have with a light car.

I think that covers everything.


So please, tell me where I went wrong, or if its wrong, or if I should just scrap the whole thing and start from scratch!!

 

[ellis8500]

It's the bend in the outer rods that's the problem. Your design diagram shows straight rods. With your bent rods you will be introducing a twisting force at the forward mount. Also, at the bend itself you will have a very high bending moment that will probably bend the bar more. It should be pretty easy to modify your design for the use of straight radius rods.

 

[2old2fast]

Look at the pic,s of ex-junks triangulated track-bar assembly, that would keep your "rotational axis" equal. However ,that's an awful lot of stress to put against those for trans. mount bolts!! . someone else w/ engineering experience needs to jump in here...

dave

 

[Corley]

I'm having trouble visualizing where your radious arms are bent. Do you have a picture of them?

 

[Keeper]

I'm having trouble visualizing where your radious arms are bent. Do you have a picture of them?

Here you go:

 

[Corley]

Oh, I see the bends. I wouldn't do that. You could gusset them if you wanted to salvage them, but I'd really rather see a straight rod there... There will be significant fore and aft forces at that point. JMHO

Corley

 

[Allen]

Sorry but this-- design is wrong

 

[Keeper]

Sorry but this-- design is wrong

Sorry but this is not a very helpful response.

 

[benT]

Sorry but this is not a very helpful response.

I agree. Statements like "that's wrong" with no other thoughts or ideas doesn't help anyone, it just pisses off the O.P and others. I thought we were past this nonsense. How about from now on, if posters don't have anything constructive to say or any sort of reasonable answer, please don't reply. Again, put up (constructively) or shut up. jeez...


Keeper, Sorry for the hijack/rant--- I wish I could help you, but I am not familiar at all with jag rear ends.



Back to regular programing...:hoist:

 

[Allen]

Sorry-- Keeper --I'M on warn status ?

 

[EX JUNK]

Look at the pic,s of ex-junks triangulated track-bar assembly, that would keep your "rotational axis" equal. However ,that's an awful lot of stress to put against those for trans. mount bolts!! . someone else w/ engineering experience needs to jump in here...

dave

Keeper, here is a picture of the bar that Dave was referring to, perhaps it might give you some ideas.
cccc

Jim

 

[Corley]

Sorry but this-- design is wrong

Allen, can you please at least attempt to contribute instead of just criticize? That type of post just doesn't help anyone, and only serves to ruin your reputation. (Guess this one I'm writing doesn't really help either, huh? Sorry, I was just disapointed when I saw your post I guess...)

And oh yes, for the record, I don't see any issue with the design it'self, just those bent rods, and yes, they could stand to be a little thicker material, but the geometry is right-on. Yes, the heims will turn a touch when the suspension goes up and down (really, not much), they are made to do that. Just be sure they are locked down nice and tight though, or they will tend to loosen the lock nuts when it twists that little bit. I'd actually prefer a rubber bushed end there, but the heims will work OK. On the original Jag. manifestation, those arms went straight forward, but everything was mounted in huge globs of rubber to take up the mis-alignment issues that had. Since you have done a solid mount, you have the geometry right.

You may find you need a different Diff. ratio. That 2:88 is pretty steep, especially if you are planning to run an OD trans. Older XJ6's and XKE's used a 3:56 or lower ratio, but it's just a Dana 44, so any 4X4 supplier or gear house can supply just about any ratio you might desire. If you are running no OD, then you may find the 2:88 OK.

JMHO,

Corley

 

[gfigms]

Hmmm ... I am planning to add a Jag rearend to mine this summer after getting back form the Nationals. I was going to follow the CCR plans to the letter. Just what is wrong with the CCR setup?

 

[Keeper]

Hmmm ... I am planning to add a Jag rearend to mine this summer after getting back form the Nationals. I was going to follow the CCR plans to the letter. Just what is wrong with the CCR setup?

Ask Ted He will tell you all the stuff he would change if he did it all over. Actually there is a post on here somewhere about it.

ExJunk. That might be the right pic, but it does nothing for me as it won't work on my rear end!

Corley, yeah the 2.88 is a little much. Especially with the 700r4. But thats what it came with and they look almost new. If I find they are tooooo bad I will replace them, but for now my 250mph top speed sticks HAHAHAHA The heims are only on the front, just for the little twist there may be, the rears are rod ends with poly bushings.

So far what I have got out of this is "Run a straight bar".

Allen - it wasn't me that hit the warn button.

 

[2old2fast]

Keeper, what I was trying to illustrate is how the rod ends rotate parallel to each other even though the link is angled.

dave

 

[409T]

So far what I have got out of this is "Run a straight bar".

Strange, me too. I'm probably swimming against the tide here, but if it were my project I think I wouldn't make any further changes without trying out what is already there. That is, assuming that I was going to put it together to test, and then take it apart for final paint. My thinking would be that one could arm chair quarterback those bends all day, but if I put it out in the street, jump on it and they don't give..........

Definitely just my 2 cents. Your mileage not only might, but probably will vary.

Jeff

 

[Gerry]

Have to be honest here. The double sheer brackets are on the light side. I would have made then from the same stock as the original single sheer ones, but doubled up.
If you want the radius rods to behave then they should be straight from the front mount to the rear. At the rear 'dog bones' (english term for the lower arms from the diff to the hub carrier) you really should make the brackets on the dog bone at the same angle as the rods, when they are straight. This takes away any bind- stress. Use straight lines on the radius rods and make the bracket to suit those lines. I ALWAYS use material thats heavier than I think it should be. One because over engineering is better than under engineering, and two is better to be safe than sorry.
In saying this I have seen R Rods done the way you have them and they are still working.
You could of course go Teds way with rubber, which will take away the sideways stress and any slight misalignment. I use rose joints (hemis) on everything. They have 2 plane movement and if they are good enough for helio'copters, they are good enough for me. Trouble is they need regular inspection and the cheap ones are really bad.

Just for your own info... I am NOT running radius rods on my Jag rear end, Just the diff pad bolts and the 2 ties straps to the diff nose. Many UK guys have done this and so far not had a failure. However we are not running Blown big blocks.

Just take take what you need from the posts, but be safe in your build. There is a LOT of experience and knowledge out there, probably best to take heed at what they say.

Dont worry it will work out for the best in the end. We want you to drive a safe car.

If I can help any more please just ask

Gerry

 

[Youngster]

I see nothing wrong with your set up keeper. It's very close to the one going together here locally. The only difference is thay we bent the forward end of the rods so the bolt holding the bushed end is centered on the trunion bolt for the axle struts. We also use an adjustable bushed end at the axle strut. You said you moved the rod all the way through it's travel without feeling any bind, that's good. That forward ball end won't be moving all that much with a 37" rod so I'm thinking you're good there too. For that matter the wheel probably won't cycle more than 4 to 5 inches unless you're jumping curbs.

I know there will be those that don't agree and that's fine .... That's why they have horseraces.

Ron

 

[Ted Brown]

Sorry I have caused a thunder storm here, as It looked like you had a different type front end mount on your radius rods, a Heim mount will let it move without the bind I was referring to, so you should be fine with your Radius rods, because in all reality, with the third member mounted solid, like Gerry says, you really don't need those type radius rods at all, they could be made using thin elect, conduit, like I used to do, as they are just riding along for looks... I myself would not have used any Heims in the short braces/tubes from the bottom connector in the center, to the frame, that needs to be very strong when a solid third member mount is used... I still can't figure out why no one wants to mount the Jag as the factory designed them to be mounted??? Young and dumb was my mistake back then, but now that I know better, it would be so simple to do it right... Just a bushing mounted cross member and strong radius rods is all that is required, very simple really... PS, You can try it as it is, but I still would not be hitting that gas pedal real hard at the start, a lot of leverage with big tires and HP... Good luck,

 

[Allen]

So you should be fine with your Radius rods, because in all reality, with the third member mounted solid, they could be made using thin elect, conduit, like I used to do, as they are just riding along for looks... ... Good luck,