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iTrader: (14)

I may be in the need of a set of offset rear control arms to clear some new shoes.

I've seen them made out of box tubing, welded together side by side. I would like to use round tubing so i can use rod ends. Now my questions are this.

1. Will welding round tubing, filling up the "valley" between the 2 pcs make a strong enough connection for a street vehicle?

2. I think, because of the offset, the arm my see somekind of twisting forces, cantilevering (?), is this something that will be enough to cause a weld like this to fail?

3. If you begin welding there pieces together, starting with a small bead down deep in the "valley", then adding 1 large bead or 3 smaller beads to fill the entire "valley" to a flat finished surface, will all of this welding on cooled welds cause any issues with weld strength?
pic of 1 large finish bead. Just a quick one for sample purposes...


4. If 3 is a no go, would putting a piece of round stock into the "valley" then welding on the two sides to the tubes be a good alternative?

5. Is there another option? i will need at least 1" more clearance off the outside edge of a 1.5" control arm.

6. Will i die if i try to do any of this?


Thanks
Phil

TraviZ

iTrader: (2)

great idea I never thought of that. How did you massage the inner fender out of the way of your tire to make your lca become the next obstacle? I am running 315 now, and with the fender (on the inside of the tire) out of the way, I would like to tuck them another half inch or so. If I could do something along the lines of yourself with a staggered lca, that would allow me either to tuck even better or run a 335.
I dont know jack about structual integrity, I dont see much twisting force unless your a corner carver. You could always try it if its cheap enough, and just keep an eye on them for stress cracks and what not.
Do you have room to align up lca brackets on the axle over to the side like that as well?

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iTrader: (14)

there will be 2 offset in the arm, so the mounts remain unchanged. I may have to do a little cleansing around the body mount.

The plan in to tuck 335/30/18 on a 12" rim. Similar to what Neil did, just without widening the fenders. Ive been measuring for weeks now and it seems that the tire/wheel will be able to fit, though i will have to do a little work to the panhard mounts, just a little on the axle mount and a little more on the passengerside mount. as for the inner fenderwell, i haven't committed to cutting yet, cause im still in the planning phase, though i will be able to clear my coil-overs with the 8.5" of BS that i will end up with, and im far enough away from the upper panhard mount, though i will have to clearance things all the way up to the coilover for best results. And i have another 1/4" i can move the rim outboard and still be flush with the fender. I just have to get my a$$ in gear and get my wheels widened.

I am a corner carver. If this pans out, i was actually going to have UMI make me a set of their poly/rod end control arms, uncoated, and cut it up and put it back together. Saves me from having to deal with welding my own rod adapters and fitting a poly mount to the arm

naterman35

I have no clue on the strength of the weld or anything like that how ever i know for me i would feel safer if i put a metal plate and welded that on...

This drawing was fast but hopefully you'll see what i mean. The red is the welds the black is the metal.

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iTrader: (14)

That a good idea too, i could make a plate to sandwich things together as well and get more weld surface, i was also planning to taper the inside of the tubes, cap off the end and smooth the inside out.
something like this
the black could be the plates

TraviZ

iTrader: (2)

the plates ARE a good idea.

naterman35

Yeah defently go with the plates. It may work i dont know much in the suspension dept. so i have no clue... But to me it looks good.

Stephen

iTrader: (12)

Instead of 3 pieces welded together, I'd make it out of 1 piece, and use a 45 deg pie cut on one side to bring it out, then a 45 degree cut to bring it back inline. Then, do it again at the other end. 1 tube, 4 pie cuts, 4 welds

That5 way, it would still be 1 solid piece, and the weld would only be on half of the tube, at one time.

Make sense? Or should I whip up a pic to illustrate it?

naterman35

Lol well i got confused im not sure if anyone else did... if you could draw one up for me that would be sweet.

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iTrader: (14)

well if a picture is worth a thousand words, whats a prototype worth



here it is, quick rough and dirty, welded together enough to bolt on, but not to drive with.




comments?


not totally following stephen, but a pic would help

actually i think i know ehere you are going, you would have to use 22.5 degree bends, so when its folded together you would get a pipe at a 45. if you cut 45's, you will und up with 90's

TraviZ

iTrader: (2)

so the notch is where the tire is going to fit right? Have you test fit that your gap is wide enough?
And secondly, will you mail me a set when you are done?

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iTrader: (14)

no test fit yet, but the gap is supposed to be in the right spot, i measured many times and held it up next to the other and it looked right. if i get ambitious tommorow i will through it on and see with straight edges.
its setup for a 18" wheel and 26"ish tire. the inner most edge is 1/2" wider than the wheel/tire, and since its 1.5" tube, im probably going to have at least 1/2" between the inner side of the tire to the bar.

its just a prototype so i had something to visualize., i can always tweak things. I wasnt actually planning on making it today, but i picked up the metal and this happened, but i did short myself on one end so you see i had to add 1.75" to one side.

RebornFromAshes

I think Stephen may have a better idea, though I would at least weld something to fill the end of each tube. I could see the tubes getting deformed from high stress where they might would hold up first.

If you are going to try this you may also want to try some destructive testing with a few prototypes. I would find the points where you can pull it apart, collapse it, and bend the two ends until the unit folded. This would help show you how strong the part is and where it is the weakest.

Stephen

iTrader: (12)

Actually, you want a 45, so once it is bent, the result is a full 90 degree bend.

I madea crude JPEG, showing step by step.

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iTrader: (14)

[quote=RebornFromAshes;3579183]I think Stephen may have a better idea, though I would at least weld something to fill the end of each tube.quote]

its a PROTOTYPE!!!! to test fitment, by no means the finished product. I dont see the need to fill the ends on a prototype that will be scrapped.
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you are correct sir. Only issue, is that when you bend the metal into shape, the anglecut side will be longer than the straight side, follow? not a big deal, but you will have ends sticking out.

I do appreciate the comments/critiquing/ideas guys. keep them comming

Stephen

iTrader: (12)

Yes, the angle cut side will be longer than the straight cut side. Not much you can do about that, except that it does give you a nice 90 degree weld seam, of bare, fresh metal to penetrate..

Or just find a shop, like a roll cage shop, that can mandrel bend the pipe for you.

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iTrader: (14)

the only dilemma i see with your idea Stephen, is that the cuts all have to be made PERFECTLY spaced and angled for the finished product to turn out straight. I dont own a machine shop, unfortunately , and the precision involved would not be practical for me to attempt. I do like the idea of one piece over my 3pc design, but the 3pc seems like the was to go, with some tweaking. well see, what happens tomorrow.
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They are hard to find in jersey, im not even sure that you can put that many bends in tubing this size in such a short span? though that would be the best way to do this

naterman35

I honestly think the way it was done in the prototype with the plate on it would be the strongest... maybe not but i feel the way Stephen said would be a MUCH Cleaner design.. but not quite as strong... but then again i might be totally wrong.

xpndbl3

iTrader: (5)

I don't understand why you don't just buy offset double rod ended control arms and not mess with what works. How big of a tire do you plan on running that you'd need more space than that? Should be well over 14" from the fender lip the offset control arms.

naterman35

I don't understand why people ask why not just buy it....Its more "custom" if you build it your self... the car has more meaning...Its cheaper...Theres plenty of reasons why people would rather build it than buy it...

TraviZ

iTrader: (2)

Building is definitely cheaper and cooler then buying, you get exactly what you want.
However, Who makes offset double rod ended control arms? I suck and can't make anything (live in an apartment) so I buy everything.

naterman35

well yeah i understand that type of deal not being able to... but the people who can why do people always say why build it blah blah

xpndbl3

iTrader: (5)

I'm running behind bars race cars LCAs, although I'm not sure they have a website. Wolfe racecraft makes them as do others, basically it's a double rod ended LCA that would have 2 different spacers to move the LCA towards the center of the vehicle more. Unless you're tucking them in 1" more than stock at least, or plan on running 315 or larger tires they aren't really needed. I still have a big gap with a 28x12.50 slick and 6.5bs on a 10" rim with the offset LCAs.
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blah blah blah, because I don't consider his design or ideas to be safe at all. What happens when those welds fail and he kills himself or people in another vehicle? His 3 tube design is nowhere near as safe or strong as a single 1 piece tube.

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iTrader: (14)

this is exactly why im posting this. I have an idea, and wanted input, see ? #6 in the first post.

In a perfect world i would love to do this in 1pc. If i can get it bent i will do that, but the point is i dont think its possible to make this bend in such a short piece and still clear the rest of the suspension.

xpndbl3, i know what piece you are talking about, spohn sell them, and ive talked to steve spohn about it. My goal is to fit a 335/30/18, i know i posted that already. thats 13.5" wide. Keeping the tire in the wheel well, even with rolling the lip, will still put the inside of the tire right smack dab in the center of the control arm, hence why i need the clearance, and i dont think the offset bushing from spohn will give me what im looking for. Im looking at 8.5" of BS

Again the pic i posted was something i threw together in a half hour, just for fun and to see how things work, im not going to slap that thing, barely tacked together, with no bushings, on the car and blast down the highway. Im simply looking for any constructive criticism that i can get on this topic.

thanks
Phil

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iTrader: (14)

also, with the tubes fully welded, both sides, with the ends capped and plates on both sides of the tubing, i see no way that its going to just break. The connection will have over twice the surface area of the tubing itself, so there is plenty of room for welding. The only other way to do this would be to use box tubing, but AFAIK that will prohibit rod ends.

Stephen

iTrader: (12)

What about moving the axle mounts inwards? Then you'd only need the LCA to offset once, rather than hafta bring it back outwards.

Shouldn't be TOO hard to fab a single inner wall, and use one of the OEM wall as the outer.

//<86TA>\\

iTrader: (14)

the shock mount is right next to the LCA mount. Not an easy thing to move. Ive looked into moving the body mount, but thats not a pleasure either

RebornFromAshes

So you made a prototype that didn't illustrate certain design features and didn't state those as being intentionally left out and then get upset when someone mentions the idea??????? The angle cuts on the tubes certainly would suggest to me that you had in mind to leave the ends open.


Any reason for using round tubes instead of square tubes? Something like this seems like it would be better done with square tubing. This would eliminate the need to work so hard filling in voids with the welder.

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iTrader: (14)

well here i stated they are quick dirty rough pieces.
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again
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box tubing mentioned. I would like to keep things round, so i could use a rod end, if the car was a drag car i wouldn't be too concerned and would not have a problem with rectangular

i understand that things may look shady,and unfinished, but that just because thats what it is, unfinished. I built the thing in 30 minutes to see how the idea would clear things like the frame, shocks, swaybars and whatnot. Im not upset about the comments, im actually happy that people are willing to look at it and give me some pointers/ideas/problems that they have. I just think people need to read the post before assuming things.


Anyway, i swapped out a control arm for my proto and it fit well and cleared most the suspension, the swaybar endlink ended up toughing the bar, so that needs to be addressed, and i messed-up my measurement for the gap, it cleared the outside of the tire, but not the inside, so i had to trim things a bit. took pics but they all came out like crap. It will require a little clearancing of the body up near the body mount to allow for upward movement, as the car sits, the offset bar is about 1/4" off the floor board, but i figured this would need to be done anyway. As it is, i have 9.25" of BS from the rotor to the offset bar, so that will be enough for the tire, though im starting to lean towards an 11.5" rim with 8" of bs as opposed to a 12" rim with 8.5", just because its a little too close to the spring for comfort


and so its clear. IF, i said IF, this things get built the connection will be braced with flat stock on both sides of the connection, welded all around, the tubing ends will be closed, there will be either 1 rod end and a poly mount, or 2 rod ends, im not sure yet. If i can im would like to have the piece bent out of 1 pc as opposed to the 3pc design, and welding will probably be done by a professional.

Stephen

iTrader: (12)

Do what Niel did to fit 335s...

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iTrader: (14)

i was actually looking through that whole saga last night, 24 pages....

he has the offset arms, though not as much cause he widened the fenders, i really dont want to do that. But i will have to chop up the inner wheel house a bit.

xpndbl3

iTrader: (5)

I don't see why a 335 tire NEEDS 8.5" of backspacing. The section width of a 10.5W tire that I plan on running is 13.1" and a simple minitub will get it done for me with 6.5" backspacing. I still have a sizeable gap between the offset LCA and the tire right now with a 12.6" section width 28x12.50 slick. Which is tucked under the lip also. With you running a 26" tall tire you will have even more room because the tire would be 1" less all around for tire radius. In the fabrication board under minitub JERRY WHO has shown a few pictures of how he is relocating the LCA to the inside of the mounts completely which should be a gap in the 17" range I'd imagine. Right now I have 14.5" I want to say between the lip and the LCA with my offset LCAs. The Spohn pieces aren't as offset as the pieces I'm running which are similar to the wolfe racecraft pieces which IMO is a much better idea than your 3 piece round tubing thoughts. The entire bumpstop area would need to be gone as well as cutting the metal back to the shock mount at least and including switching to smaller diameter springs, such as the wolfe racecraft setup that uses the 2.5" diameter ones instead of the 4" ? or larger stockers.

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iTrader: (14)

ive got coil-overs, so spring clearance is not an issue.

Im useing 18" wheels, xpndbl3, so a 335 tire fits on a 11.5-12.5" wide rim, thus the excessive backspacing. with the tire, and the backspacing, the outside of the wheel will be just about flush with the finder, and about 5/8" off the coilovers

you have me intrigued by the wolfecraft pieces, i will check them out

87 formy

I just skimmed over this thread, but how much space do you actually need to clear your tires? I know sjm manufacturing makes an offset LCA, i think it's 2 rod ends and instead of being in the center, is pushed out to the inside. If that would be enough, it might be a better choice. Just trying to give you some options

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iTrader: (14)

well, think of it this way. The inside edge of the tire, will be 1/8" from the inside edge of a 1.375 control arm. I looked at the wolfe piece, and i dont think it will work


since we all love pics

the red in the control arm, the grey is the tire

what i have measured, the width of the body mount in 2.375", so with my 1.375" control arm, that would leave 1/2" on each side of the bushing, plus the 1/8" i have left in the arm, gives my 5/8" total room to fit something in the stock mount, and be totally flush with the tire. there are no straight arms, even with no bushings on the inside, that can accommodate this. I think the thinnest ones ive seen are 1"od?

xpndbl3

iTrader: (5)

to put a 12" rim in the same exact spot that my 10" rim is right now would be 7.5bs since i'm running 6.5bs, that would be 1" of extra rim on either side. I would imagine that would be doable with the offset LCAs. If not you will have to look at that minitub thread i posted info above and move the LCA to the inside of the factory mounts. Also dennis bernzal or whatever his name is on here was running 335 viper tires so maybe look him up as well.

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iTrader: (14)

really? hmmm.....

i've been following the minitub post, and jerry's ideas are good.

If you did add the 1" to the outside of your rim, would it be outside the fender? flush with it? Im trying to keep my tire as tucked as possible.
Dennis has the 335's, and they stick out big time, looks badazz, but would get me a ticket quick

xpndbl3

iTrader: (5)

well since we're running the same section width tire it would still be tucked. Just your rim is 1" wider in each direction. here's a pic of 6.5bs with 10" rim which would be the same offset as 12" rim with 7.5bs on a stock width rear.

Sonix

iTrader: (1)

LCA's should only be taking tension and compressive forces, no twisting or bending. Since you're using rod ends, this will be the case.

With your existing design, the weakest point of the arm will be your welds, since that area will take the entire force. So look in the direction of force (along the arm), and think about how much area the tubes take up (ok, checkmark), then how much area the weld takes up. The weld will have to distribute the load to the tube again. I don't think just filling up the tube 'cavern' with weld will do it. Doing that, as well as adding a 1/8" plate across the top and bottom and welding it should be fine.

What size, thickness, and material will this be made out of?

Another option is to make a complete one, then see if there are destructive testing places nearby. Basically put the thing in a press and measure the force. See how much force it takes to collapse it, and see where it failed. Hopefully not at the welds
Then with some calculations you can figure out how much force you need to be able to withstand in normal conditions. Throw in a safety factor and you're good.

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iTrader: (14)

Schweet!!!!

All hail Spohn Performance!!!!

Been talking to Steve about this and he said he could build these for me!!!! and he doesn't seem to have any issues with strength so long as he does it and not me with my epic welding skills

He also tells me it is too tight to be bent, kinda figured that.

Other than that the option of last resort is billet aluminum, though i would hate to see the cost of a 6"x6"x24" chunk of aluminum, let alone the machining cost

we'll see how this plays out....

Sonix

iTrader: (1)

"billet" aluminum? A solid aluminum bar? I wouldn't consider that at all But yea, if he can build 'em for ya, give'r torque! Be sure to post up a picture for us all to oogle

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iTrader: (14)

the aluminum was a bit of a joke, i dont think its too economical to build a set of 2000$ control arms.

Pic's will happen of course when/if this happens

white91formula

iTrader: (4)

i didnt read through everypost all the way, but why not have the arms bent out of a single piece

and also if you are going to run bushings on the ends of the control arms like that with round pieces your going to want to get a hole saw the size of the tubing and notch the ends for the bushing pieces to sit into, it will be much stronger and easier to weld

i would never run a 3 piece design like that, weather there are plates welded or not, but thats just my .02

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iTrader: (14)

yea, a lot gets missed by not reading, though i dont like reading longwinded posts either.

they cant be bent, not possible, too tight, too short of a piece. The one i made was just a prototype to bolt on the car to check for clearance. Spohn is supposed to actually make them for me once im ready.

Aside from that, the prototype is complete, it clears everything and im ready to go. Once i get the go-ahead from Spohn, i will send it away, and send the wheels out to be widened. Then the fingers will be crossed and the cutting will begin.

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iTrader: (14)

Finished tweaking the arm and sent it over to spohn today, so hopefully next week Steve will let me know what he thinks

scooter

iTrader: (11)

I dont think this is a safe idea either. Like someone else said the tubing is weakest at the welds. I am surprised 83crossfire hasnt posted in here yet. I think if you need an offset you should go with rectangle like Neil did or like Stephen said and make square (45) cuts in the round tubing.
I just dont want to see someone get hurt.

Stephen

iTrader: (12)

With the right aluminum alloy, you should be fine

Sonix

iTrader: (1)

Aluminum's aluminum's aluminum. They're all still FCC crystal structures and therefore have a finite lifespan WRT cyclical loading. I'd rather have steel personally,

Stephen

iTrader: (12)

Not really. Yes, they are all BASICALLY the same, but some are WAY stronger than others. I made my spacers for my Tahoe, out of 6061-T6, when I was a CNC machinist.

That would be like saying steel is steel is steel. Some grades are MUCH stronger than other. Stainless steel vs Carbon steel, for example.

Sonix

iTrader: (1)

Yea, strength varies, but the basic properties of the metal are the same. They can be a lot stronger, but they have a finite cyclical life because they are aluminum, and will eventually fatigue and fail. Steel has an infinite cyclical life if you don't load it past... what, 60% of tensile strength?

Steel is steel is steel WRT to cyclical loading (with the exception of FCC materials such as austenitic SS, 300 series IIRC).