Trying to find a How-To on Control Arms

[mitch_04]

I asked this at Pro-Touring's website and didn't quite get the responses I was hoping for. Maybe I asked the question wrong...

Anyways, I'm looking for a good How-To on building control arms. I'm looking for information on which bushings to use, ball joints, what diameter/thickness of tubing, etc etc.

Obviously safety is a concern, but since I have no way that I have the ability to weld I don't see the point in arguing it. I could post pictures of my welds, someone could say they aren't mine, etc etc... I've seen it go 'round and 'round before. I have built my 4-link from scratch, z'ed and c-notched my frame, built a transmission crossmember, and engine mounts. Aside from telling you this I don't know what else would make someone more comfortable about me building them.

I hope someone can give me some help, I have to build 2 sets...possibly 3.

[Vince@Meanstreets]

Thats a loaded question.
We need more info.
It would depend on the car, vehicle weight and usage.


What is your planned camber and castor build in. What motion ratio are you planning? What spindle? Coil over or conventional spring.

Material would depend on vehicle weight and a general idea of forces.

Upper is 1 1/2" .120 DOM average.
Lowers are 1 3/4" .120 DOM average.

I would recommend a factory (replacment or equivilant) cross shaft, bushings and balljoints.

[mitch_04]

Although I do have a few vehicles I need to make control arms for, I'm more trying to get (or be pointed to) a thread going on the choosing of components for control arms. My vehicles that are needing some control arms are a '50 3600 that will have IFS/IRS and an '85 C10 that will need front arms, but like I said, I'm hoping to get a good reference thread going that people can look into and find answers to their questions.

I see you recommended some average sizes of tubing. When do you decide to go up or down from there? Obviously weight will have something to do with it, but I'm also assuming the length of the arm and motion ratio (spring placement) would affect it as well. Do you use any programs to determine feasibility or is it from experience?

I have a Student version of AutoCAD (benefits of being in the military), an engineer friend who can show me how to use it, and a machinist friend to help me build the components.

[Vince@Meanstreets]

There is just a bunch of information that you would need.

You have to know what would fit the truck and the space you have available.
I would start with wheels and tires then build around that. That way you can figure a control arm shape that will not interfere with wheels tires, brakes and other suspension components.

Next would be spindle. Then build a lower control arm to fit that package. Once you get the lower arm you can then make the calculations for the upper control arm length and placement.

Performance trends has a nice program you can download online.

I would advise against making too many custom parts such as bushings. I would look to what is available then build around it. AFCO, Coleman and Speedway have all the bushings and ball joint combos that you would need. Keep serviceability in mind.

Honestly, your going to have to build something then improve on it. I like to build full size working proto types out of scrap. Nothing I could drive, just use to check steering and travel. Once you have a base you can use a program to perfect the design.

[mitch_04]

I appreciate the response. I actually do plan on purchasing the software, I forgot to mention that. I'm not going to go crazy custom, I plan on using some easily replaceable off the shelf parts whenever possible. I am curious what you (and others) prefer to use for bushings. What company, what material, etc etc. Someone from Ridetech kicked in on my thread at Pro-Touring, it's starting to pick up a little steam. I would like to have opinions from everyone who builds them, can't have too much information!