My jag rear radius rods

[Keeper]

And that is why I wanted to post this. Get it all aired out

I will take the advice and leave them as is for now. I do plan on running it before blowing it apart for paint so any changes can be made without fear of scratching the paint.

Gerry, I will have no problem doubling the size of those mounts. The current ones are a touch over 1/8 inch, but I made them long on the back side for more metal to the frame. As for over building everything, I am doing that as well, every piece of tube on this is 1 inch .219 wall DOM.

Ted, what would you use in place of the heims on the inner short mounts? I had a clevis on there before but switched to the heim when I remade the mount to a double shear.

See that's why I love this place, all the different opinions/views can be expressed with out all the drama.

 

[Ted Brown]

And that is why I wanted to post this. Get it all aired out

I will take the advice and leave them as is for now. I do plan on running it before blowing it apart for paint so any changes can be made without fear of scratching the paint.

Gerry, I will have no problem doubling the size of those mounts. The current ones are a touch over 1/8 inch, but I made them long on the back side for more metal to the frame. As for over building everything, I am doing that as well, every piece of tube on this is 1 inch .219 wall DOM.

Ted, what would you use in place of the heims on the inner short mounts? I had a clevis on there before but switched to the heim when I remade the mount to a double shear.

See that's why I love this place, all the different opinions/views can be expressed with out all the drama.

I do believe I would make the ends weld on, fit them to the brackets on the frame, with bolts that come close to fitting your tubing at both ends, after all they should never have to be changed, the length, I would also do two more pointing straight forward to the trans cross member, well they can point up a bit, as that is the direction the bottom of the third member is wanting to go... I just may start making a bushing mounted cross member for the Jag rear ends, with the coil springs able to mount in a few different positions, like from 19 inch center to center of the top mounts, to 24 inches wide, for a really heavy chassis and driver. plus a good set of radius rods, a single tube, probably 1 3/8" OD, because you want no bending of that tube, because it holds it all... Just like the stock lower control arms from the factory, but longer...

 

[Mike]

Sorry but this-- design is wrong

Who knew design critiques were also available in CliffsNotes versions?

 

[Corley]

Keeper,

You said "I do plan on running it before blowing it apart for paint so any changes can be made without fear of scratching the paint." That's the ticket, go that route. Keep in mind though, that when/if this were to ever fail, it could most likely be an all at once failure, so be sure before you paint it all pretty. Still, I say runner as is, it ain't all that bad.

As Gerry points out, those radius rods should not see much stress if the diff. mounts are solid enough. I DO think perhaps from looking at the pictures of the yella' fella that Gerry may have beefed up his lower arms. They were designed to take in/out forces only, not fore/aft forces, but could be beefed to handle both. Seems to me like perhaps Gerry's are now more the shape of an A frame member, converred with metal instead of just a big 'I'. Doing that could mean eliminating the radious rods all together unless you are hell bound for performance. That's probably what I'd do to "fix" it. Am I right Gerry?

(To those who say that's too much fore/aft force out at the end of the new 'A' frame member, I say that a large percentage of newer cars and SUVs with rear wheel drive and independent suspensions are doing just that. Also, lot's of front wheel drive suspensions use only the 'A' frame members to support fore/aft motion.)

CB

PS Caution: Old Fart's story of historical insignificants to follow... I remember back when I was a teen, I needed a front axle for a go cart, and I had a major brain fart. I welded a couple of Ujoint crosses to a single leaf out of a Model A spring so the Ujoints could act as king pins for the front wheel steering. A yoke cut off and an axle stub welded in on the other side to act as the axle, and Viola, front suspension. (Of course camber changes a bit on bumps..) I then welded the middle of the spring to a singe tube frame (actually an old drive shaft). All the local "experts" said the welds to the spring material would never hold, the spring would crack. We ran it for years, (in fact a grand nephew still has it), and had the only go cart around with front suspension. Who knows what will work and what will not work without either analysis or better yet, testing. (I don't advicate welding to spring material these days though...)

 

[Allen]

Radius rods-from the hubs forward. They will mount on an IMAGINARY LINE- where the lower H --arms pivot to eliminate bump- steer. You can also use the rear tie bar. There is also a front tie bar that will use torque--stays to attach to the chassis. The tie bars are needed since the rigidity of the original CAGE--the IRS sits in is removed.

 

[Youngster]

Keepers center section is solid mounted to the frame so unlike the stock Jag CAGE mounted in rubber, the dogbones/ axle struts along with the brace on the bottom of the third member housing will eliminate the need for a trailing arm like the stock Jag. As Ted says, the RR/ trailing arms could be made of some light tubing. If the center section is mounted in an energy absorbing mat'l then there is a need for a more substantial arm/ rod.

Ron

 

[Allen]

Keepers center section is solid mounted to the frame so unlike the stock Jag CAGE mounted in rubber, the dogbones/ axle struts along with the brace on the bottom of the third member housing will eliminate the need for a trailing arm like the stock Jag. As Ted says, the RR/ trailing arms could be made of some light tubing. If the center section is mounted in an energy absorbing mat'l then there is a need for a more substantial arm/ rod.

Ron

Yes Youngster. But-- by for bolts jmho

 

[Gerry]

Corley.
The bottom arms are 1/2 round section both front and back with a diagonal brace between them Then the whole lot was covered in sheet. With the diff being a solid mount and the diff straps in place it will hold together. Light rear and make for tyre spin rather than loads of grip. This T will never see a drag strip, its a cruiser. We are 99% sure, too much foot and the tyres will just let go, in fact I can just manage to move the rear sideways on a smooth floor if I heave like a wrestler. I think it will have enough go for me and most players on the street and after so much time, effort and money it would be waste to break it. Always thought it took a good 6 months to get really used to a car and its behavior. With 8 x 2" throttle bodies a little throttle will go a long way. The one BIG no no is not having the diff straps at the correct angle.

There have been many T with Jag IRS and no R Rods in the UK. Never heard of one having a problem. Also take a look at a front wheel on any modern cars, when it goes over rough ground and see how much it moves fore and aft... its frightening.

G

 

[Youngster]

Yes 4 bolts and the pinion struts ... that's 6 points in all. Most solid axles are mounted to the frame rails with 2 bolts in the radius rods and one frame mount in the sway bar.

Ron

 

[Corley]

Allen,

Wait just a dog goned a minute, you are from Morro Bay, Bobby Nunes was raised and spent most of his life in the Paso Robles / Atascadero area which is only about 20 miles from Morro Bay, you both use the same "hehehe" phrase,,, Is "Allen" by any chance your middle name? Are you and Bob Nunes by any chance one in the same? I am very suspicious about this... I apologize if I am wrong, but some of your forum entries sure sound a lot like Bob Nunes criptic entries to me...

Corley

Mike, sorry if this one violates the rules, and you may ban me if you must, but I just had to wonder about this...

 

[2old2fast]

In all this talk the only forces I've seen discussed are torque under power, going forward, I'm curious as to how much thought has been put into severe braking force ? I'll be the first to admit I had my head up my a$$ thinking where the torque would be under acceleration, now I'm trying to comprehend braking force , all out at the hubs/carriers right?

dave

 

[Gerry]

In all this talk the only forces I've seen discussed are torque under power, going forward, I'm curious as to how much thought has been put into severe braking force ? I'll be the first to admit I had my head up my a$ thinking where the torque would be under acceleration, now I'm trying to comprehend braking force , all out at the hubs/carriers right?

dave

Under braking you are just stopping the weight of the car and rotating the car towards the ground. This is one reason the front brakes are more effective than the rears. Under acceleration you are moving the weight of the car plus putting all that torque through the tryes which in effect is trying to rotate the car around the back axle. But thats another reason for the diff tie straps to be right.

Gerry

 

[Keeper]

In all this talk the only forces I've seen discussed are torque under power, going forward, I'm curious as to how much thought has been put into severe braking force ? I'll be the first to admit I had my head up my a$$ thinking where the torque would be under acceleration, now I'm trying to comprehend braking force , all out at the hubs/carriers right?

dave

The brakes are mounted inboard, so any stopping force is applied to the solid mounts. The calipers are attached to the pumpkin.

 

[2old2fast]

Yep there again , head up my butt .. thanks


dave

 

[Allen]

Allen,

Wait just a dog goned a minute, you are from Morro Bay, Bobby Nunes was raised and spent most of his life in the Paso Robles / Atascadero area which is only about 20 miles from Morro Bay, you both use the same "hehehe" phrase,,, Is "Allen" by any chance your middle name? Are you and Bob Nunes by any chance one in the same? I am very suspicious about this... I apologize if I am wrong, but some of your forum entries sure sound a lot like Bob Nunes criptic entries to me...

Corley

Mike, sorry if this one violates the rules, and you may ban me if you must, but I just had to wonder about this...

don't no what you talking about ? sorry

 

[Ted Brown]

I think that everybody has forgotten the very big difference between solid mounted (all steel) and 4 bar bushings, (Soft mounted) have you ever tried to straighten a bent nail with a rubber hammer? Try the shear thing with anything mounted in a soft bushing... With the complete rear assembly = third member, 4 coil springs mounted to a bush mounted cross member, as it was in the stock cage... and 3/8" connector bars (ft. and rear) and a 3/16" to 1/4" plate on the bottom, holding all the lower arms in good tight connection with the third member... Now this whole assembly can move a bit as the suspension allows the wheels to move up and down... With all these bolts running through soft bushings, it is now very hard to shear most any bolt... BUT, in the solid state, there is NO give at all, and now the shear factor is or has enough leverage to shear most any size bolt with no problem, or twist it out of it's mount without too much problem... think about the length of the lever trying to shear those bolts, clear out to the end of that big tire... Take a piece of bar or tube, something strong, that same length, and see just how much power you now have yourself, you can do some major damage with that bar, but if it were in rubber, not so much... Those lower main control arms are made to handle any torque that a Jag could dish out, in all directions, starting, braking and side motions, they seemed to handle road courses without rear end suspension failure for years, so in a light weight T that rear should last (mounted in rubber) the life of the car...

 

[Youngster]

Ted ... can you give us the weight of a Jag sedan?

Ron

 

[Ted Brown]

Weight of a Jag sedan, Gerry jump in here, as I have never had a complete Jag, just the rear ends, some are made for pretty heavy bodies, because they are not only wide, they mount the coils at 30 inches wide at the top, a T Bucket only needs to be 20 to 21 inches wide, cuts down on the leverage that the springs have, (gives the leverage to the T frame and body) lets the car move up and down easier... NOTE: Nothing should be solid mounted to the frame when bushing mounted, and using Radius rods...

 

[Differen T]

Please indulge me while I think out loud

I'm looking at the mounting setup as a big A frame. The axle shaft is a fixed length.The lower arm locating the rear wheel is a variable length and it is this variable length that keeps the tire in a vertical plane as the wheel moves up and down in relation to the chassis. The inner end of the lower locating arm already has two mounting points therefor any additional mounting points added to it must be in the same plane. If the blue line is the plane for the location of the inner mounting points then the mounting point for the radius rod must be in the same plane (this also includes the height of the plane as measured from the ground). So much for the easy stuff. The difficulty that comes with adding a radius rod with this setup is that the lower locating arm is a variable length therefor the radius rod must do one of two things, either let the lower locating arm slide in its rear mount (as in a bird cage type of mount used in dirt track cars, except it must allow an in and out as well as a rotational movement) or the radius rod must automatically change length with wheel movement (which defeats the purpose of adding the rod).

Any type of radius rod mounting that does not compensate for wheel movement will have some binding which will limit suspension travel causing the rear axles to become solidly mounted, which in a harsh bump condition will result in an instant loss of control. I do not say this to scare you because I don't think the binding will be instantaneous in normal driving. In fact the binding might not happen in your allowable range of suspension travel. All you may experience are changes in camber, caster and/or toe. Remove the rear springs and check for binding through out the range of suspension travel and observe any changes in alignment (if they are not easily seen the vehicle should be drivable).

A properly mounted radius rod should improve the handling and traction of this style of Jag rear under high horse conditions. The biggest problem with the stock setup would seem to be wheel hop because the stock mounts on the lower control arm are close together and a long way from the wheel.

Al

 

[Ted Brown]

Al, Sorry but if it is mounted like a factory setup, the radius rods (which I call flapper arms or control arms) mount straight forward of the hub, just clearing the rear tire... No kind of radius rod helps in the least with traction on this Jag type rear suspension... This is a ride setup, not traction, built for COMFORT!!!