I have some 2" 6061 tubing with .5 wall, is it strong enough to make control arms for my 3rd Gen Dodge diesel?

At first I was gonna say, .5" hell yeah its plenty, but then it occurred to me that this is likely aluminum, right?

If so, I'd say google a metals rating table and try to compare to .25" steel tubing as that is probably the most commonly used for links


But I think 6061 is probably strong enough. Do you beat on it off-road a lot? How will you be making the links? welding, etc.? I would say the use factor is probably the most crucial here as I think structurally it would be fine, but if you start hitting them on rocks you may begin to run into problems.

This is my street and tow rig where it sees’s only moderate off road use during hunting season. I will thread the tubing and use rod end.

I would avoid it if I were you. 2"x0.500 tube would be normal to a little bit big for a diesel like that if it were made of steel. 7075 aluminum might be fine with that thick wall but I wouldn't want 6061 under 900lbs of Cummins. Threading into aluminum will also be kind of bad news bears, as it won't hold the same as steel would for the same size threads.

Just my take on it though, you can build anything you want.

why the new control arms? I'm assuming you came across this tubing cheap or even free? remember, their is no such thing as a free puppy. I would just buy some control arms if you need them. I know bolt on parts aren't as cool as custom made (home made) parts but someone has already done some sort of failure analysis on the bolt on parts that i wouldn't want to do on something I drive down the street. You have a heavy truck, now consider having to explain to several people how your "custom control arms" failed and you hit grandma head on when she was on her way home from church. Keep a mature handle on whats cool and or respectable on tow or trail rig and your life will be alot easier.

I would avoid it if I were you. 2"x0.500 tube would be normal to a little bit big for a diesel like that if it were made of steel. 7075 aluminum might be fine with that thick wall but I wouldn't want 6061 under 900lbs of Cummins. Threading into aluminum will also be kind of bad news bears, as it won't hold the same as steel would for the same size threads.

Just my take on it though, you can build anything you want.

Have you ever seen a stock control arm from a dodge diesel???? Just so you know the stock control arms are about 1"x2"x1/8" and I am not sure if it is a full 1/8"

But to anwser the question of the original poster yes it should be plenty strong. The company's that make the longarm lift kits are only using 2x.25 tube and the longarms control arms are almost twice as long as stock

Yeah, but he's right on the threads not holding as well in the aluminum. You can try it, but you may not be successful. I wouldn't expect catastrophic failure, but they may wear out prematurely at some point.

And yes the stock stamped arms are much less beefy in appearance than the material he is talking about, but aluminum and steel have incredibly different properties and this will have pretty serious effects. Think about stock control arms on IFS stuff. You don't normally see them on 3/4 or 1ton rigs, only on the half ton stuff, and they are cast, and they usually aren't threaded.

I'm not saying that they would be the best choice but I am saying that they would be plenty strong for control arms and if he is going to use 1.25" rod ends the thread would hold fine also

And your statement about ifs stuff on 3/4 and 1ton trucks has no merret because only chevy has ifs under those trucks and I think the lower arm is aluminum

Have you ever seen a stock control arm from a dodge diesel???? Just so you know the stock control arms are about 1"x2"x1/8" and I am not sure if it is a full 1/8"

But to anwser the question of the original poster yes it should be plenty strong. The company's that make the longarm lift kits are only using 2x.25 tube and the longarms control arms are almost twice as long as stock

Yes I have seen the control arms on a Dodge, everyday when I drive mine. The problem stems from both the change in geometry (Round tube is weaker in bending than square/ rectangle) and the change in material. As I stated before a 2"x0.500 tube would be fine made of steel and I wouldn't see any problem with it made of 7075 aluminum but 6061 has me a bit leery of the idea.

The heat treat condition of the aluminum also will make a big difference in strength.

so you are saying that all for the companies that are making lift kits with control arms for dodges are making them too weak???? because they are only 2inx.25in steel tube


2"x.5" would be complete over kill for steel

I would avoid it if I were you. 2"x0.500 tube would be normal to a little bit big for a diesel like that if it were made of steel. 7075 aluminum might be fine with that thick wall but I wouldn't want 6061 under 900lbs of Cummins. Threading into aluminum will also be kind of bad news bears, as it won't hold the same as steel would for the same size threads.

Just my take on it though, you can build anything you want.

I'm pretty sure I already said 2"x0.500 made of steel would be fine or big. 6061 has nowhere near the strength of even a mild steel though. For comparison, here are yield strength of different aluminum alloys compared to that of normal steel:
6061-O: 8 ksi
6061-T6: 40 ksi
7075-O: 15 ksi
7075-T6: 73 ksi
1018 CR: 54 ksi

As you can see, even heat treated aluminum has a significant reduction in strength compared to steel. If the 6061 is not in the aged condition it has less than 1/5th the strength. While the larger wall thickness makes up for some of that strength, not nearly as much as going to larger OD would. All I'm saying is that making a link with those dimensions out of aluminum would need more thinking than just calling it OK and going with it. Especially if its going to see street time as the original poster said it would. I'm sure if you do any sort of bending calculations a 2"x0.250 tube made of steel will be much stronger than a 2"x0.500 tube made of 6061-O.

so you are saying that all for the companies that are making lift kits with control arms for dodges are making them too weak???? because they are only 2inx.25in steel tube


2"x.5" would be complete over kill for steel



What don't you understand about the difference in properties of steel and aluminum? Yes 2x.25" is fine when made in steel, but this guy is talking about aluminum; which has different properties.

And fine, take away the IFS part of the comment, you still don't see control arms made out of aluminum on ANYTHING that big and heavy.

What don't you understand about the difference in properties of steel and aluminum? Yes 2x.25" is fine when made in steel, but this guy is talking about aluminum; which has different properties.

And fine, take away the IFS part of the comment, you still don't see control arms made out of aluminum on ANYTHING that big and heavy.

i do understand the properties of aluminum the reason you dont see anything aluminum on big and heavy stuff is because normally you have to use 3x as much aluminum to have the same strength as steel and being that aluminum is about 1/3 of the weight of steel there is no reason to use it because of the huge cost difference

if you go back through this thread you will see i never said anything about me telling the guy to go out and buy aluminum he stated that he already had it and was wondering if it was strong enough

Point is though, that it is not strong enough. Yes he already has it, great. Yes its a thicker tube than you would need with steel. Still, this heavier tube made of a weaker material is weaker than the normal design you see made of tube. The thicker wall helps to make it a stronger tube, but not enough to outweigh the change in material.

Now as an extension to this question: If you wanted to make it out of aluminum instead of steel (a perfectly feasible idea) the OD of the tube should be increased before the wall thickness. Going to a bigger OD has a more dramatic impact on strength than wall thickness.

Related to this all: once again, the heat condition of the aluminum makes a big difference, 6061-O (I would guess that's what this is, I don't have a lot of aluminum experience) is much weaker than 6061-T6. Much like using 4130, if he were to tap the control arms for the rod ends and then have the part aged, it would be a much better idea for making arms out of.

i do understand the properties of aluminum the reason you dont see anything aluminum on big and heavy stuff is because normally you have to use 3x as much aluminum to have the same strength as steel and being that aluminum is about 1/3 of the weight of steel there is no reason to use it because of the huge cost difference

if you go back through this thread you will see i never said anything about me telling the guy to go out and buy aluminum he stated that he already had it and was wondering if it was strong enough


Well based on that, he is going to use .5" aluminum and if most stuff is .25" steel, then the aluminum still wouldn't be strong enough since you said you need 3x the aluminum to equal the steel strength. That means in your eyes, .5" aluminum would be equivalent to .1666666667" steel, which would NOT be strong enough on a cummins truck. Just saying :D

Well based on that, he is going to use .5" aluminum and if most stuff is .25" steel, then the aluminum still wouldn't be strong enough since you said you need 3x the aluminum to equal the steel strength. That means in your eyes, .5" aluminum would be equivalent to .1666666667" steel, which would NOT be strong enough on a cummins truck. Just saying :D

i said that the companies that are making LONG ARM kits are using 2"x.25" the normal lift kits where they use the short arms (i little longer than stock) they are only using 1 3/4"x.25"