Need a How-To: Building Control Arms

[mitch_04]

Does anyone know a link for a good How-To on building control arms? I would like to see how they determine which ball joints, bushings, diameter of pipe, etc etc. Found a couple online but nothing that had everything I need.

[astroracer]

How much suspension design background do you have? Just asking because you DEFINITLY need some of that before you even think about building a control arm...
Mark

[BMR Sales]

Not sure why you would want to Build your own, when you have plenty of choices of where to Buy some already made that you could have by the Weekend to Install on your Car

[CampbellshotrodsAZ]

I'm assuming this is probably for a not so common car, and nothing is available?

I'm curious myself, as I'll be building a suspension setup for a 64 Volvo probably next year, bolt on parts aren't yet ready for that car!

[mitch_04]

A touch more negative responses than I was hoping for!

I need to build control arms for my '50 3600 because it is going to be entirely custom. I could purchase control arms for my '85 C10, but I'd rather put my money towards Supension Analyzer, raw materials, and learning.

I'm in no rush to have it done by the weekend. I also could hand my pickup(s) off to a shop to have everything done as well, but I enjoy building things myself and take pride in saying I've done it. While I'm sure the next response will be whether or not I'm capable and how safety should be taken into account. I believe I am plenty capable, but I sure can't prove anything to you over the internet. I built my triangulated 4-link from scratch, worked out very well using the guidelines that ExWestRacer had given me. I have C-notched and Z'ed my frame, built my own engine mounts and transmission crossmember, read books on suspension (and all of Ron Sutton's threads) until my eyes bled. However, non of the books or threads tend to discuss ball joint selection, TUBE diameter and thickness, etc etc. I've seen a few things here and there that show how people make theres, but still no specifics on how they go about choosing what bushings/ball joints/etc..

Josh, I hope to get somewhere here and I hope it will help out yourself and others as well. Maybe add what you would like to know as well?

[marolf101x]

"I would like to see how they determine which ball joints, bushings, diameter of pipe"

The very first question is, are you modifying the OE geometry or building something from a clean sheet?

Once you know what the arm should do (increase camber gain, increase caster, provide extra clearance, etc) you start at the chosen spindle.

Ball Joints:
The spindle will have a taper for the ball joints. If you choose to use the OE part you find out what taper it has, then locate a ball joint with the appropriate taper, length, and height (if you are not using a tall spindle, and you want increased camber gain you need a taller ball joint). Then you decide whether it needs to be press in or bolt in. After those considerations you locate a ball joint that matches what you want.

Bushings:
You have to decide what type of bushing you want for your intended application. If it's purely street use you want rubber. If it's hard core you want delrin or bearings. You then locate a bushing that fits the application. Again, if this is OE you know what the mounting width will be. If clean sheet you can make whatever you want.

Tube Size:
You need to know what the car weighs and what you intend to do. If it's light and street only, you can get by with thin wall material. If it's heavy and sees track time (increased load) you want something larger.

Basically you need to tell us the specs of the vehicle and what you plan to do with the car. We can then make suggestions as to what you should use in all cases.

[mitch_04]

Thank you sooo much Britt, a great start to what I'm looking for!

All right, I'll try to give as much info as possible. The '85 C10 may or may not be kept in the stock geometry. I would like to purchase suspension analyzer, enter in my specs, and see if there is room for improvements. I'm assuming there probably will be. The weight of the pickup will be closer to 4,000 lbs than 3,000, street use with no track time. I'm leaning against rubber bushings since the air ride will need as much rotation as possible and rubber would tear (correct me if my thinking is wrong).

The '50 3600 will be clean sheet, with spindles from a Chevy Colorado (bolt in wheel bearings, disc brakes, fits 15" steel wheels to keep looking original on the outside) and IFS/IRS. The weight will be close to 3,000 pounds, street driven. Rubber is a possibility on this one as it's main goal is ride quality.

Your post made me think of a few more questions.
1. I see you left out polyurethane, was that accidental or do you not recommend them for some reason?
2. Is there benefits to press-in, thread in, or bolt in ball joints?
3. Do you know of a good place to find these "universal" parts?
4. Are there any universal rubber bushings for control arms?

Let me know if there is anything else you need to know that I can come up with. I really hope this thread turns into great reference!

[Motorcitydak]

Will something from a place like this help?

http://pitstopusa.com/c-132107-chassis-suspension-suspension-front-control-arms.html

You can get off the shelf arms that may either fit your application or make the mounts fit what you need. Using an upper control arm from guys like these will give you tons of options for adjustment and suspension changes. The lowers you can get the kits and have them completely adjustable too

Poly is actually not a bushing material, unfortunately it is cheap and easy to make of put out there so it is very common to see used but it does not do a good job at being a bushing. It does not allow any twisting of the joint, it will not absorb vibration like rubber would. Like Britt said, you are better off with either rubber for more cushion or bearings for precise control but increased NVH

For the ball joints be sure you first find one with the correct size and taper, then the height, then the type of fit. Screw in or bolt in are easier to remove/replace but you should not go thru them very often. The first thing you should do is mock up the frame rail and the spindles with wheels and tires on to check ball joint clearance. I see that you want 15 inch wheels but that will make it an issue for you trying to get a good scrub radius. You need the ball joints close to the center of the wheel if possible. If you are flexible on wheel size you may want to consider corvette spindles and bearings. Great aftermarket support and availability of brakes

[astroracer]

Lots of good info here. Getting Performance trends will give you the ability to design a working suspension but the program is far from intuitive. Starting with one of the canned designs (Corvette) will give a set of goals to design to.
When I design a suspension I start with the steering rack. That is what "drives" the entire design. Building your arms around an existing suspension I.E., Corvette rack and brake corners, would be far easier then trying to build one using mismatched components.
Try to use off the shelf components as far as ball studs and bushings are concerned. Much easier to find in stock when the time to rebuild arrives.
As far as what "style" of ball joint is used, match them to the intended spindle. I used off the shelf Moog components for the van to fit the modified Astro spindles I used.
If you want to see what it takes to design and build a custom front suspension, check out my BadAst build thread. The actual build starts on page 9. I hope you can gain some insight to what you need to do. :)
Mark

[marolf101x]

1. I see you left out polyurethane, was that accidental or do you not recommend them for some reason?
I'm not a fan of poly for a bushing. As stated they don't provide much NVH mitigation over "solid" bushings, and they make a lot of noise if not serviced at regular intervals.
We actually injection mold our Delrin bushings. Why do we do this when others obviously machine them from round stock? Our bushings have 13% PTFE (Teflon), so they are self lubricating and don't require maintenance. Delrin with PTFE is relatively inexpensive in pellet form, but almost 10X the cost when you buy it in a rod. So most of the machined Delrin bushings you see do not have PTFE, and require a grease zerk.

2. Is there benefits to press-in, thread in, or bolt in ball joints?
As stated, bolt-in and thread-in allow you to more easily change them. However, we use press in quite often as they take a little less space.

3. Do you know of a good place to find these "universal" parts?
Please see #4 below.
Also, I use this a lot:
http://www.moogproblemsolver.com/
http://www.fme-cat.com/application.aspx
It will at least give you a Moog number for the OE application (so if you use Colorado spindles, look them up by Colorado)
I don't know of anywhere that lists ball joints by taper.


4. Are there any universal rubber bushings for control arms?
You can find a lot of the parts we use to build our control arms here:
http://www.ridetech.com/store/components/rod-ends-bushings-and-sleeves/
The Delrin bushings are not on the site, but I've asked the web guys to get them up there.

[mitch_04]

I am loving the way this thread is going, just what I was hoping for! Thanks to all of you for your replies, they are very helpful. I know I have been listing the parts I will be using, but I'm trying to get this to become a thread for any and all users. If it seems like I'm hesitant to talk about my specific build, that may be why...well, that and I'm still "in my head" on the 3600 build.

Just to get a break down of what I am grasping so far.
1. Rubber is best for ride quality, flexes more than desired for performance.
2. Polyurethane is used mostly because of it's low cost but it's benefits are not significant enough to justify choosing over metal/Delrin.
3. Metal/Delrin are best for performance but will transmit the most NVH. Delrin without teflon needs to be greased.
4. Ball joint taper/diameter must match spindle, and height must either match original or be adjusted to change suspension performance.

I am sure I'm forgetting to list something, but that's just the nature of the game. Now a few more questions...

1. Do Delrin bushings need to be machined for press fit, or should they just match the inner diameter of the steel sleeve?
2. How do you grease the Delrin? Hollow bolt with zerk, on the outer sleeve, or...?
3. Do you have a reference for purchasing Delrin rod with and without PTFE?
4. Is there any ball joints that should not be used on the street? I've searched through catalogs such as Speedway and seen a few "race" ball joints, didn't know if there was a specific reason they are to not be on the street.
5. Can I email you or anyone at Ridetech to purchase Delrin bushings or are they not sold individually?
6. As I took it, rubber bushings are usually vulcanized to the inner and outer sleeve. When using rubber bushings in a universal application, are they simply pressed into the outer sleeve or...?

I am sure, again, that I am forgetting something and I will think of it as the day goes on. I would like to thank everyone again, these posts are just what I am searching for. I will probably use the original style ball joints, they are bolt in and should be easy to adapt.
http://www.amazon.com/Moog-K80997-Ball-Joint/dp/B002FS72MY
Couldn't get a good picture of the upper one, but our point of sale program (I work at a parts & repair store) shows the picture as a bolt in as well. I had considered going with the C5 spindle and possibly even adapting the control arms, but then I would really like to keep the outside of the vehicle looking original with steelies and white walls. I also have a '79 Z-28 that may be a more pro-touring build down the road, but for now it's my pickups that are getting my attention. I had read a great article where someone had an engineer and a machinist for friends, drew up his entire suspension from scratch. It was a great article and I'm sure I could find it again, but it had talked about how he started with the rim/tire and worked his way in from there. That's similar to what I'm trying to do on my 3600. Anyways, I hope this thread keeps on going as the information is really starting to roll in!

[marolf101x]

I'll keep answering your questions, but let's look at this from a reality stand point. . .take your '85 C10 for this example.
We just went through a complete re-design of that front suspension, so I'm intimately familiar with it. Assuming you are basing your new design off the old design, let's look at this:
Case 1: rebuilt OE suspension
Case 2: custom designed whatever you build suspension

Since you state that the '50 will be more "street" I'm assuming the '85 will be more "pro touring". However, you also stated you wanted to retain 15" wheels. I'm hoping that statement was for the '50 only. Here's why:
As you won't be getting maximum grip from larger tires, the largest disadvantage you'll see with Case 1 is the rubber bushing deflection. The best designed suspension (read. . .one with fewest compromises!) won't be able to get enough out of small tires to make a difference.

If you are working on the '50 and just want something nice on the street and don't want to spend a ton of money I suggest you look at the Crown Vic front suspensions guys are using in F100's recently. That would give you rack and pinion, disc brakes, and geometry good enough for cruising the street.

Now on to the specific questions:
1. Do Delrin bushings need to be machined for press fit, or should they just match the inner diameter of the steel sleeve?
They should be "line-to-line" or slight press. The Delrin will conform to the steel as it has no other choice. Any gap will be pronounced as a "clunk" or "tick" during travel.

2. How do you grease the Delrin? Hollow bolt with zerk, on the outer sleeve, or...?
Typically you have two bushings with a gap in the middle. The zerk goes in that gap.

3. Do you have a reference for purchasing Delrin rod with and without PTFE?
McMaster Carr

4. Is there any ball joints that should not be used on the street? I've searched through catalogs such as Speedway and seen a few "race" ball joints, didn't know if there was a specific reason they are to not be on the street.
I try to use a Moog or equivalent replacement (Proforged is a GREAT company for these parts). Moog just makes it easier to find a fitment.
I do this as they last longer (typically) and are more easily replaced (read. . .any auto parts store if you pick something common)

5. Can I email you or anyone at Ridetech to purchase Delrin bushings or are they not sold individually?
Yes. They will be on the website sometime soon, though I know the web guys are working on a number of things at the moment.
Just send it to [email protected]

6. As I took it, rubber bushings are usually vulcanized to the inner and outer sleeve. When using rubber bushings in a universal application, are they simply pressed into the outer sleeve or...?
Yes. We make our own, but also use many OE replacement parts. Again, Moog makes it easier to locate a common part.

[mitch_04]

The C10 will have larger rims and tires, and although it's not what I would consider pro-touring, it is being built to handle better. I have seen guys swapping Crown Vic front suspensions, although for the life of me I can't remember what they were swapping them into, but a large part of this is the enjoyment I get building parts from scratch.

Let's take yourself for example, and please correct me if I'm wrong. Being the Director of Engineering, I'm assuming you are more than capable of designing parts. Let's say you left Ridetech and, for conversations sake, were on a very strict budget. Would you build your parts from scratch, or spend a large section of your budget on new parts?

I am definitely not saying I'm at your level, I'm not even in the same building. However, if I can (with the help of great people like yourself, Ron Sutton, and others who chip in) design the suspension in Suspension Analyzer and build it using parts recommended by experts, why not? I love spending time working on my projects and having the pride of building something myself. I could send off my pickup to have someone else build my turbo header as well, but it's probably going to be over $1000 with most of it in labor. I'd rather build it myself and as long as it's functional (maybe not perfect) and better than original, I consider it a win. I take my saving and put it somewhere else, either a different part of the vehicle or in a different vehicle.

I probably could have built the control arms without starting this thread, but after this thread is finished I will know more and have a better finished product. I have done large amount of research prior to this, but it's been more about suspension basics (and a little more advanced). Sorry if this seems like a rant, but I just want to explain why I'm not just buying every component. I could buy the engine built, tranny built, etc etc, but I enjoy the building! I'm sure others are like me on here, and maybe they are curious as well. Maybe I'm the only one...

[Auto Rod Technologies]

Talk to taylor (jeebus) on this forum, He has MMW and could make you a custom set..

[mitch_04]

Thanks for the reference, I've seen a bunch of C10 guys using MMW control arms, but I just plain enjoy building my own parts! I guess if I try and I fail I can always purchase, losing the cost of my materials. However, if I try and succeed it will open a huge door for me as far as options go. I recently started a side business restoring cars (main job is generic auto repair) and all my profit from that goes towards tools. I don't spend any of that money on myself, so things like Suspension Analyzer that I would never normally justify purchasing are now able to be bought under the guise of shop expenses! I plan on purchasing a large amount of tools that I won't be proficient at immediately (mostly sheet metal forming) but will come in very handy with time and experience.

Seem's like I'm making it complicated, but since there isn't a book available on designing and constructing your own A-arms (probably due to liability) I am hoping to find the information here. I always try to learn the theory through books, then practice until I feel I fully understand, then build. I've done this with stereos, transmissions, bodywork, etc etc...

I'd like to add that everyone who is currently constructing control arms from scratch had, at one time, never built one. While I'm not saying I will be the next RideTech, there is no reason I am not capable of learning how to be proficient at the task. I tried out for the Special Forces a few years back and, although I didn't make it (medical withdraw during tryouts), during the training I learned to never give up, never quit. The training stuck with me even though I hadn't made it, allowing me to complete a few marathons, very long ruck marches with high weight, and other generally difficult things.

Kind of a off the topic rant, but I always like to explain where I'm coming from. It's hard to separate the guy who jumps on a forum bragging about how amazing he is and the guy who is actually capable since it's all basically a front, but I hope some of this backround helps.

[marolf101x]

"Would you build your parts from scratch, or spend a large section of your budget on new parts?"

Neither. What I've done is start with something "good" and go from there.
Here's a link to pics of my third gen Camaro with the entire front of my C5 Z06:
http://projectawdcamaro.com/3rdgen.html

I also have a long term all wheel drive, all wheel steering first gen project that uses C5 as well (mainly since I can run a drive shaft through the upright)

Don't get me wrong, I'm not trying to dissuade you from building your own arms. I love building things as well.
I just want you to be aware of as much as I can think of.

Back to the regularly scheduled program. . .

[mitch_04]

I do love 3rd gens, I hope to pick one up someday. I had considered a C5 swap in the 3600, but when I decided to keep the exterior appearing stock it wasn't possible due to the 15" rims. I believe I have looked into your AWD Camaro site before, you should get a thread here as well!

I currently can't think up any more questions at the moment. If anyone else has advice or questions I hope they jump in as well. I'm sure when I get to it certain things will pop up, but until then I believe I have the information I was looking for.

[Twentyover]

You may want to look at the Locost fraternity

http://locostusa.com/forums/index.php?sid=28e7950a22e989acc2d0965be36ea47f

for some thinking on fixturing and building control arms. Scale (diameter and wall thickness) would need to be increased as Locosts generally come in between 1200 and 1500 lbs

[GaRys69]

Check out the SAE training site, some classes you can do online.
They just sent me the Spring Education Guide full of Chassis and Vehicle Dynamics Technology.
http://training.sae.org/

[mitch_04]

The SAE training site is very neat, but I think it's above my budget. I looked at one of the suspension classes and I think it was around $1200!!!

[GaRys69]

Yeah for me also, some are lucky enough to have their company pay for it.

[Eric Howell]

Pick a cross shaft, pick a ball joint, pick tube size and build a jig. (not my pics) These are from a C6 based GTM build. First is rear arm, last two are front. Hope this helps. Here is the photobucket I stole these pics from http://s926.photobucket.com/user/jchracer/library/?sort=6&page=1


91985

91986

[Rifleman_Racing]

http://www.spcalignment.com/images/stories/catalogs/SPC_Cat_2013-web.pdf

Starts at page 114. This can probably get you where you need to be. Ive hobbled kits together for odd cars a few times with these.

[mitch_04]

That catalog is a great go-to for parts! However, it did spawn another question.

Is there any benefit/problems with longer vs shorter control arm shafts?

[mitch_04]

Anyone have an answer for me? Please? :)

I would assume that the wider control arm shaft would be better for arms with more clearance for things like shocks, coils, or bags. Maybe stronger against torsion "wrapping" when the brakes are applied? Smaller arms for tighter situations...

Any of these assumptions correct or does someone have some information that would help?

[Motorcitydak]

You are correct, no geometry advantage to having a wider cross shaft, only for packaging purposes. The pivot locations will be on the same plane, regardless of their distance apart