Lar's Bar's Build

[Justin]

Mainly whether you have existing arms that use a 1.25" shank joint. A 1" heim is has an ultimate radial static load (basically load before failure) of about 50-60,000 lbs. If you put enough force on your 1" joint to break it, you've got bigger problems than a busted joint. Most of the existing arm designs use 1.25" shank heims, which are usually good for around 75,000 lbs. SPC doesn't offer a 1.25" joint currently, and they're a really cool design, in part because they've got some extra sealing that other joints don't. If you want to run them, you'll be going with a 1" joint. The Metalcloak joints that I think we'll be doing the group buy on are unique because they use a rubber bushing that has a ball molded into it, rather than a fairly stiff polyurethane bushing. Because the ball is molded into the housing the rubber is pulled and stretched as the joint moves, making it self-centering and potentially setting it up for a longer service life since there aren't any parts sliding against each other. There's also more and better cushion due both to the design and because you're working with rubber instead of polyurethane. OEMs don't use polyurethane, but the aftermarket does in part because it's cheaper to manufacture.

Short version: You're fine with either, just depends on which brand joint you want to use. Digger might be able to describe the SPC stuff better, as I don't know as much about how their joints are put together. The only other real benefit to a 1.25" joint is that they're more common should you ever need to replace the entire assembly.

[Gunnibronco]

What determines whether you need 1" or 1.25"?

edit: Didn't see Justin's response.

1" or 1.25" refers to the shaft that threads into the radius arm.

The Duff, Cage, etc arms all accept the 1.25" rod ends. Digger has mentioned that this is over kill & a 1" rod end is adequate.

[Gunnibronco]

Digger might be able to describe the SPC stuff better, as I don't know as much about how their joints are put together.

I think, the SPC joint is essentially a sealed heim joint. A rubber boot is built in, helping keep the joint clean. Maybe there is more to it, but that is what I've understood.

[ZOSO]

SPC does make a 1.25" shank joint. Just not in the 2.625" width. Only available in 3.25" width. So that just means a larger bracket and bolt on the frame side. A duroflex joint is available 1.25shank 2.625" width.

[Justin]

Gunni, I think there is some padding in there somewhere, but I'll let digger answer that one. Zoso, thanks for the correction, you're right!

[Eck]

I guess whatever everyone else is doing, I'll do the same. Just let me know...

[Digger]

The SPC joint is built like a standard automotive ball joint, but is through-bolted instead of having a stud. Besides the mounting method, construction is the same. The inner metal has a spherical feature that mates to a hard plastic race (typically) which is held within a metal housing.






This means the joint has no "give" to it like a bushing would. They are used where precision of travel is important or where high loads could destroy a conventional bushing. For radius arm ends a bushing is a better choice for ride quality over a Johnny Joint, xAxis or rod end (heim).

On my rig, I replaced the xAxis joint with a Clevite bushing. Clevite is the trade name for the rubber bushings typically used by the domestic OEMs. Metal Cloak joints also utilize Clevite from my understanding. This allows the front axle to move back and forth a little in reaction to hitting potholes, rocks, bridge seams, etc producing a better ride quality, because these jolts are dampened out and not transferred to the passengers.





I would recommend using the Metal Cloak joints for the radius arms. Save the xAxis for building a multi-link suspension (like my rear suspension) where the control arms can have an xAxis in one end and a bushing in the other.

[ZOSO]

so there you have it. Duroflex joints for all. I like the xaxis joints cause Im a believer in supporting local companys but i'll go with the majority.

[Justin]

Cool, thanks Digger. I'll get to work on figuring on pricing on all this.

[ZOSO]

You gonna do them all 1.25?

[Justin]

Probably, unless someone wants something different. Easier to all do the same thing, and likely to get a better deal.

[ZOSO]

I guess it's time to send out PM's to the ones interested and double check the quantity. Im in for sure.

[Justin]

Update: Still working to confirm a date, should be mid or late Feburary as my weekends are sort of a mess at the moment. I've been in touch with Metalcloak and they were unsure about doing a group buy and not able to offer much of a discount anyway. I just talked to High Country 4x4 (Metalcloak vendor) and they're working to get me pricing for everything that we'd need. Will get a separate post up when I've got more info.

[Justin]

Question: Kirk and I have talked a little about the design of these and want to build in a little more caster than stock. I'd also like to move the bend further down the tube to add a little more tire clearance. I suspect that we can kill two birds with one stone by moving the bend much closer to the C and rotating the C slightly from vertical. Any reasons why this is a bad idea?

[hockeydad4-22]

Question: Kirk and I have talked a little about the design of these and want to build in a little more caster than stock. I'd also like to move the bend further down the tube to add a little more tire clearance. I suspect that we can kill two birds with one stone by moving the bend much closer to the C and rotating the C slightly from vertical. Any reasons why this is a bad idea?

Ok - two things.

First - I have no idea if we can make changes or if they are advised at all, and second I understand moving the bend - but what does adding the caster do? how does this benefit us (and how does it hurt - in other words, why doesn't everyone do this if it is a great idea?)

Yes - this is the noob in me asking silly questions again

[Justin]

Caster affects a couple of things. More caster=a stronger tendency for the front wheels to self-center and fights the tendency of the front end to wander, especially on grooved or heavily worn pavement. Correct caster also improves handling under heavy cornering loads. As the tire rolls under load it wants to pick up the contact patch on the side of the tire that's towards the inside of the turn. Caster angles the tread away from the turn, keeping the contact patch flat and maximizing the amount of rubber that's touching the road. More caster also increases the amount of effort needed to turn the steering wheel, so manual EBs tended to run less caster. Power steering allows more caster with equal comfort.

[Eck]

So why doesn't everyone do it in the first place then?

[Justin]

Caster isn't really adjustable on the stock suspension. Longer and will buildin a little, as will radius arm drop brackets.

[crawlercreations]

The only issue I see with putting the bend closer to the axle is shock location. My shocks are on top of the arm like stock still but if I had bent the arms closer to the axle I would have had to mount the shocks on the side of the arm, thus not gaining any real tire clearance still.

[Eck]

Caster isn't really adjustable on the stock suspension. Longer and will buildin a little, as will radius arm drop brackets.

So with the 2 changes you guys are talking about, will additional changes to the stock set-up be required to use the extended radius arms?

[Justin]

Ill post a pic of my arms for an example. I'm thinking the bend will be about halfway down instead of near the heim, so it should impact shock location.

Eck, you will probably want to change out the shock towers to take full advantage of the travel, but the lower mounts should be close enough to stock to still use what you've got. The frame brackets will need to be welded to the frame and the stock ones cut off.

[Eck]

Ill post a pic of my arms for an example. I'm thinking the bend will be about halfway down instead of near the heim, so it should impact shock location.

Eck, you will probably want to change out the shock towers to take full advantage of the travel, but the lower mounts should be close enough to stock to still use what you've got. The frame brackets will need to be welded to the frame and the stock ones cut off.

Thanks. I did know about the brackets already but just wanted to make sure there wasn't a list of changes needed. So it appears shock towers are the only additional thing.

I'm trusting all the research, knowledge, and work you guys are doing on this so whatever you think is best, I'm on board. Thanks!!

[ZOSO]

I since I have spent 2 days laying under the bronco, I got to looking and measuring. Have we decided on a length? I was thinking 10" over stock would be about perfect. What do you think?

[Justin]

I was thinking about 10" as well.

[ZOSO]

Sweet.

[Justin]

That seems to be the sweet spot between taking up too much real estate and getting plenty of extra flex. I need to measure my arms and see where they sit.