Long Arm Kits

I was looking into Long Arm kits, on Claytons site he is using a 3-Link set-up and states: "3-Link setup up front providing excellent on-road stability and off-road capability".
I have heard others say that the 3-Link set-up is the way to go yet I was surprised when I looked into Rubicon Expresses new Long Arm Kit it is a 4-Link system and they state: "With its 4-link design front suspension system, it can easily be turned into a trail dancer" making a point it is a 4-link system.
I would think that if a 3-link design was the way to with long arm suspensions RE would have built their new LA system this way.
Am I mis-informed or thinking wrong when comparing 3 & 4 Link system?
THanks

3 link, 4 link...bla, bla, bla. i think they both use the same thing. they must just count their links differently. they both use radius style long arms with the upper link mounting to the lower arm on both sides and they both use a track bar.

matthew

RE:



clayton:

http://www.claytonoffroad.com/hap_main.html
i can't link directly to the picture, sorry

What I was told by Clayton he was using a 4-link system, and later moved to a 3-link system. I think the pictures on his site are the older 4-link picture.

BobCSmith said:

What I was told by Clayton he was using a 4-link system, and later moved to a 3-link system. I think the pictures on his site are the older 4-link picture.

Click to expand...

ok, that makes sense. i was just going by what i've seen and what is on his site. here's a picture of his setup. (old setup i guess?)

clayton:

another clayton:

While we're at it, could anyone please explain to me why these long-arms work? As far as I understand it, the upper links would resist flex. When the axle flexes (i.e. one wheel up, one down) one long arm have to twist upwards relative to the axle, the other down. But the top links seem to stop this motion... ? What am I missing? (I haven't seen this kit in action, just can't understand how it works)

thats probably why he's going to a 3 link with only 1 upper.

matthew

My understanding is a 4-link designed puts a twisting stress on the front axle. I was talking with Kevin at kevinsoffroad.com, who is also releasing a new long arm kit for the XJ (looks like a nice design), he was explaining how a 4-link design puts extra stress on the froont axle. What surprises me is if this is known to happen why would RE release a 4-link system on their new kit.

When you consider the insane amounts of flex you can get from a 4 link like claytons old setup, I'd really think you're splitting hairs by asking for MORE LOL....

I have the Clayton 4 link setup about to go on...and man, the amount I've seen the clayton equipped XJ's flex scares me LOL....The front and rear of my truck are going to have vastly different flex characteristics.

The Kit on my truck allowed Ken to just walk over and pull a Rubicon ZJ sping right out with no fuss....I can't imagine needing more.

Now concerning the twist on the axle...whether you're running 3 or 4 links to the body are the dynamics that differnt to allow MORE flex and less stress?

My guess is that some people would still like to drive their jeep on the road afterwords... thats why I went with RE, and it worked KICK ASS in Moab

BobCSmith said:

What surprises me is if this is known to happen why would RE release a 4-link system on their new kit.

Click to expand...

cause they've been selling same design LA kit for TJs for couple years and it works fine.
if you're so concerned, just unbolt one upper arm when you get to the trail and put it back on for the ride back home.

I spoke with Rubicon Express yesterday, they told me that the Long Arm Kit for the XJ will not be ready for actual release until late January. They only have a prototype on one of their vehicles now. Are you running a a converted TJ kit?

I'm not as much concerned, more or less curious and doing my research before purchasing one.

haha, I remember a post a ways back about this kit, back then they were shooting to have it out for June and it was big topic because everyone was wondering why they were advertising it.

Anyway, Clayton makes sweet kits, I put his 4 link on my Grand and love it, it's incredibly beefy and very high quality. I do wish it was a 3 link. He's a pretty cool guy though, I'm sure he'd give me a good deal to change it over.
The four link still flexes better than short arms, rides incredibly smoother too. Clayton used a triangulated rear 4 link on the grand that works great, gets lots of flex. Anyway, they're strong. You can bet if you break it he'll take care of you because you'll be the first one to do that.
Just FYI, RockKrawler designed their kits to bypass the stress placed on the axle from the "radius" arm design by usin a radius arm on one side and a regular arm on the other. They've had some disasterous problems with their torque arms breaking. I'd think you wouldn't have this problem with Claytons' kits since he builds them so strong.

Since it hasn't been mentioned here yet I figured I state one of the problems of the 3 link. Since there is virtually no resistance to droop in this suspension design your downward travel will be more uncontrolled than a 4 link. Unless you have really really soft rear leafs or some sort of low resistance rear coil setup a 3 link will tend to bias all the flex of your rig to the front suspension potentially screwing up your "balanced" flex. This problem is exactly why products like the currie anti-rock off-road sway bar was made. To give a controled progressively greater resistance to droop as the suspension drops. This promotes equal flex front to rear which is a good thing

I'm not saying three links are bad but in some situations a little controlled resistance (some call binding ) is a good thing.

?????????

Functionally I don't see any difference between the two designs being discussed. As Sarvemr points out, neither is a 3-link or a 4-link -- they are both 2-link, or radius arm.

The factory front suspension is a 4-link -- there are 4 links from the axle to the chassis. When the front axle moves up and down relative to the chassis, the geometry of the unequal length upper and lower arms keeps the caster angle mosr or less constant.

With the Clayton's "4-link" or the RE (which appears to be derived from the Clayton's), the upper arms no longer connect to the body, they connect to the lower arm. That means when the axle moves up or down relative to the chassis, the caster angle changes because the entire axle and arms simply swings in a fixed radius around the point where the lower long arms mount to the chassis.

This is a radius arm suspension. There are only two links. To see a 3-link suspension, look at the rear suspension of a WJ. In fact, Clayton's web site states that it is a radius arm setup.

Like TOZOVR, I don't see how omitting the passenger side UCA helps anything. Trying to envision how things would move, it seems to me that doing it this way would be asking to have the diff housing torque up and rip itself off the driver's side axle tube.

When using two UCA's with a radius arm style suspension droop will cause more negative caster and compression more positive caster. If you flex the front suspension each side will be trying to rotate the axle housing in opposite directions which is why anything other than rubber bushings on a double UCA radius arm setup tends to rip UCA mounts off. The softness of the rubber allows some required movement. This action of the rubber bushings at the axle squishing adds a progressive resistance to suspension flex.

If you only use one UCA the axle twisting associated with two UCA designs is gone allowing for uninhibited suspension flex until the shocks bottom out. Depending on your setup this system may allow the front to flex to easily potentially offsetting a balanced front to rear suspension.

I jsut got Claytons new kit and its badass. I cant wait to drop it on this weekend. Then i might be able to flex a little

All I know his kit is f'n awesome, cant wait for the rear 4 link to come out.

And RE probably wont have their kit out till Next june

Cheers,

Nik

so whats the difference in design between the NEW and the OLD kit? does he use only 1 upper axle control arm mount?

thanks?

this is an old post but i would like to thank bender for being the first person to make me think about this disadvantange of a 4 link. also i think there is a problem with counting links. the radius arm setups are 2 links, yes. perhaps they are counting the panhard rod as a link. if that is a link then the cherokee uses a 5 link setup from the factory. i would consider that a link myself as it does affect suspension movement.