Radius arm make over

I've decided to try and see if I can get some kind of flex out of my set up so the plan is to sleeve my current radius arms with 1 3/8" ODx 7/8" ID .250 wall DOM and put 3/4 heims on the ends.
I've fabbed up some brackets from 3/8" plate steel and I ended up changing my design so I had to use the material I had already bought for the project. It would have been a lot easier to use the main plate coming off the frame with some 2 1/2" square tubing with a tab coming off of the bottom but oh well.
The radius arm brackets will mount just behind the tranny X-member with 4 bolts on the side and 2 on the underside of the frame. I'll eventually make a removable crossmember to tie the radius arms together.
I got all the heims, heim hardware and DOM tubing fron spidertrax.com. They have these heim dust boots i'm gonna try out too...couldn't hurt.

So here's some pics...first one you'll see what i have to work with on my truck. That radius arm is hanging there on it's own and if I put some weight on it, it doesn't go down much further if at all so you can imagine what that's doing for flex or lack therof.
Next pic is a template of the main plate i'm working from and the rest of the pics are the finished brackets ready for paint.

 

[Byrd91]

I'm going to give some advice here that is totally theoretical because I don't have an SAS, but some (a lot) of the solid axle flex problem comes from having two radius arms (one on each side). Unlike the TTB in which the radius arms are independent of each other, on a solid axle the radius arms are redundant. They are both performing the same function, and since the axle is solid, unlike the TTB, they will bind no matter how long the RA are. Thats why you see a 3, 4, 5 links, etc, and more specifically wristed radius arms. Just think about what your axle does on extension or compression, it follows an arc. If one wheel is going up and the other down there is a twisting force on the axle ( solid ) because the two radius arms are going the opposite way in the arc. All of your flex is in your C bushings. To test the theory grab a pencil (axle) with your fingers (radius arms) and move it like an axle flexing. Your fingers have to slip to allow articulation, the RA bushing mounts at the frame have less to do with it than the radius arms. People like to make pins to make wristed arms more road friendly but I don't "think" that those are even necessary.

The difference it makes:
http://www.pirate4x4.com/forum/showthread.php?t=270094&highlight=wristed


And an idea that I didn't even think of but that would be perfect for you and more stable on the road.

http://www.pirate4x4.com/forum/showthread.php?t=294387&highlight=wristed

Sorry for the hijack.

 

[Felix]

You are correct in aspect of it. Yes the non wristed arms with the solid axle or non wristed axle and solid arms act like a sway bar. The reason for making the arms longer is to reduce caster and the arching motion when the system cycles. This also eases the binding by giving more rotational torque from making the arms longer and making the axle move more to create the same amount of binding force.

Not trying to hi-jack DB_1's thread and not knowing if he has the same idea as me or not. I am going to extend my arms with hiem joint mounts and wrist the passenger side one also. This will in essence releave all the bushing bind the front axle can produce.

I am not an enginer but have pretty good understanding of mechanics and have talked to many fabricators for off road systems for the Early Broncos. This is pretty much what they have told me also. I think that I just made it take more words than it should have.

 

[410Fortune]

flex as good as coilovers only because you are removing the spring and the shock mount and replacing them both with a single axis mouting point = freedom!

Air shocks seem to be a good choice for a rock crawler, trail truck, but what about those long drives to the trail??

Looking very nice Dave, wrist that arm and you will find hapiness.....

If I ever go SAS (I love the TTB, when its set up right) I will do a true 4 link to help eliminate the need for the wristed arm......

 

[DB_1]

All very good points and well taken but I have to disagree with you on your point about the RA bushings at the frame having less to do with limiting flex than anything else. I would say, in my case anyways that it was limiting it equally if not more than anything else. As my first pic shows, the radius arm is hanging by the stud in the bushings and only allowed for 2 maybe 3 inches of up or down travel before the urethane is totally compressed. Not what I call total freedom of movement. I will agree that the front C-bushings limit movement but more on a twisting axis than anything else and now thats where my flex is now limited. So i've relieved some up and down movement but now the twisting action of the C-bushings is the binding point. I figure if I can relieve one of those binding points I can achieve better flex than what I started with. I'm not out to be a ramp champ and will never be as long as I run what I have. If I could do it all over again...3 or 4 link plain and simple, i've seen enough of them in action and work very well.
The radius arm I have would take more fabbing to make it work, it would be easier for me to get the standard issue EB cast arm and go from there. I just wanted to improve what I had already since I've invested a lot of money into it..

Yeah Jaime, i've heard they arent to road friendly and that may be the one thing that prevents me from getting them. I was thinking if a torsion style sway bar like Currie's anti-rock would help on road manners any.

 

[bmxking5]

Very nice job, DB_1

 

[410Fortune]

Dude the way you are building your truck is the RIGHT way to do it, look at what you have learned.

I am now installing engine #4 and transmission number 9 I think, hahahaha
Of course if I could go back and build this truck again I could take all I have learned and do it for 1/8 of the $$$ and in about 1/8 of the time, but where is the fun in that?

I am dropping in the 5.0L tomorrow for the trial fit, this truck will be running by Feb and it may be the only EFI 5.0L/4r70W/4x4 Bronco II with OBD-II electronics on the planet Roll cage, body, and more suspension mods have been put on the back burner for this swap.......but what can you do when your $2500 "bulletproof" A4LD decides to let go after just 6 months of service? MUWAHAAAA

Nice work, top notch. I can see the natural progression of your truck, fab skills, and knowledge..THATS what this is all about...
Anybody can pay to have it built, but I'd rather wheel with people who know, how, why, and what to do when it breaks.....

 

[DB_1]

Thanks BMX

Yeah Jaime, nothing like building up your own truck even if there's a big learing curve involved. A few yrs ago, I never would have thought about or attempted some of the mods I'm doing now...I guess rolling your truck changes things, lol.

Thats gonna be awesome once that engine swap is done and if it breaks down
at least you can say "thats a 5.0 that doesnt run in there!" lol, j/k

 

[Jefe]

And here I though my control arm brackets were beefy. Now I'm gonna have to go rebuild mine.

Looking good Dave

Dude the way you are building your truck is the RIGHT way to do it, look at what you have learned.

Of course if I could go back and build this truck again I could take all I have learned and do it for 1/8 of the $$$ and in about 1/8 of the time, but where is the fun in that?

Anybody can pay to have it built, but I'd rather wheel with people who know, how, why, and what to do when it breaks.....

Well said.

 

[410Fortune]

hahaha hey didnt you hear? 5.0L's dont break down! They are ALMOST as reliable as the pushrod 4.0L!!!

hahaha
Its the 4r70W slushbox that I was after, man thats going to be so nice! Ever driven a late model 5.0L auto Explorer??? Now take away 1500#, add 4.10 gears and a clean slate for new mods with an endless supply of aftermarket performance adders......should have done this 8 trannys ago......

 

[Jefe]

As for air shocks. . . Off road they'd be great, but I'd be worried that you'd have some serious sway problems onroad even with them valved stiff. But I have yet to see a heavy rig with them on, plus the ranger has a much lower CG than my Explorer.

 

[DB_1]

And here I though my control arm brackets were beefy. Now I'm gonna have to go rebuild mine.

Looking good Dave

Thanks Jefe,
Your brackets seem to be holding up very well for all you've put it through.
As far as the air shocks I was hoping the new Fox 2.5" airs would be better than the 2.0" version. There isnt much info out on them yet since they are still being tested.

410,
you have 4'56's right now don't you? Going to 4.10's will put you in a better power band then the 4.56's with 5.0?

 

[410Fortune]

nope 4.10.
with the EFI 5.0L, 4R70W and 33's I will be sitting pretty with 4.10's.
If I kept the 4.0L I would have eventually gone 4.56, so that $$$ now goes towards the 5.0L....(read expensive t case adapter)


With the 5.0L and the right cam and power adders my 4.10's should even be okay when I run my 35's to say....Moab.

 

[RangerX]

...I guess rolling your truck changes things, lol.

Funny how that happens... :roll:

 

[Diff Whack Daddy]

...I guess rolling your truck changes things, lol.

Funny how that happens... :roll:

Cheers :roll: :roll: Couldn't agree more.

 

[DB_1]

See, you guys know where i'm comin from

 

[RockRanger]

so how did they hold up after the weekend of wheeling. I didnt take a look to see, just wondering if all is well. I know we took a couple of VERY hard hits in the wash trying to race colin back to camp. If they didnt bend I would think they would be plenty strong.

 

[DB_1]

Looks like they held up pretty well (knock on wood) Luckily everything is soft out there for the most part so like when you crest some of those hills the brackets would plow into the ground a bit cause they hang down so low.
I'll be building new brackets eventually that will tuck up higher but until I decide what I'm doing as far as front suspension that will be on hold. I think those hits you felt Matt were my track bar smacking the track bar bracket. There's not much clearance on the up travel so there's another thing that has to be re-done...lol.

 

[RockRanger]

I was more talking about the bouncing we did when we were trying to race colin back in the washes. Glad to see it held up well.

 

[DB_1]

Yeah, that's what I meant to say but didn't in the last part of my post was that was the trac bar you felt hitting the trac bar mount when we were racing in the wash.

 

[FROADER]

Ah...racing in the wash... brings tears to my eyes.