4 Link? which is better?

[duane67c-10]

On a triangulated 4 link I see this done different ways, the top links on the center of the rear end going outward to the frame or on the axles near the frame going to the center of the crossmember. which is better? and why? also what determines the length? is the top suppose to be longer or shorter than the bottom bars?

[PrerunnerRob]

It all depends on how you want it to work, I'm sure someone more knowlegable will chime in.

[LONGHAIR]

I think that decision is really based on available space....as in, which ever fits best in your application. I don't know that there is a performance advantage either way.

[Kontrol Phreaks]

On most trucks it comes down to available room on the chassis, or the rear differential you're running. There might be a fuel tank, exhaust, shock mounts, etc. that are limiting your room to work.
The GM 10 bolt rearends, the center section is cast steel, and you're not supposed to weld directly to it. For that reason people will come off the axle tubes right next to the center section, or off the outside end of the tube next to the frame rails.
A Ford 9 inch housing, the center section is formed mild steel, which you can weld to. With those you can run the bars off the side of the center section, or directly off the top if you have room.
As long as the bars have enough of an agle to them they'll work properly and keep the axle centered. Remember to tack the suspension first and cycle it through the motions before you finish weld the kit in. There might be some point where the kit binds up and you'll want to correct that before you move forward with the install.
Hopefully this will help you out on your project and good luck.

[duane67c-10]

THANKS!! I will check out your site.

[BioMax]

It sounds simple, but there is actually a LOT more than that to it. It's just that most "daily driver" types don't need to concern themselves with roll centers and roll moments...

[Kontrol Phreaks]

There are many different things that are critical when installing a 4 link system, and we could be typing here all day. But as Max stated, for the daily street driver those critical options decrease because of the "required" motions / movements required for the street. Max is an extremely intelligent individual, and an even better fabricator. I've been a witness to many of his projects over the years.

[ElkyRacer]

So setting up a triangulated 4 link for a street truck, you pretty much only have to worry about getting good triangulation, to keep the rear centered, getting your pinion angle right through the movement, and getting your instant center right? Anything else? Ive been looking into a lot of this getting ready to set up front and rear 4 links for my Jeep, and there are a LOT of variables that the rock crawling guys take into consideration. I just wasnt sure what I needed to be sure and pay attention to in a street driving setup. Am I looking too far into this?

[N2TRUX]

Originally Posted by ElkyRacer

... Am I looking too far into this?

Not at all. If you don't ask, you won't know. If you don't have adequate triangulation, the rear will walk around. You need as much as possible within the space you have available.

As stated, get max triangulation then verify that it doesn't bind.

[BioMax]

The only other thing that I would add is to try to keep the bars near parallel to the ground at 1/2 travel (as best you can while still being mindful of the instant center.) I have seen many rock crawlers that have TONS of induced roll steer because of the severe angle of their link bars. On the trail it's not that big of a deal, but try to avoid that on the street. It can be nearly undriveable at speed.

[ElkyRacer]

Good deal, Ill make a note of that to keep around. Thanks Max!

[ElkyRacer]

I was just doing some thinking(scary help me!). Would it be best to set the top and bottom bars as close to parallel at ride height? I see you said parallel at 1/2 travel, do I want my ride height set at 1/2 of the suspensions travel? I know the bags have an installed height measurement, but most people set that, make sure they can get full dump and go on about their fabbing.

How much separation should I be shooting for at the axle and at the chassis mounting points? Im going to be raising the bed floor up to clear the notch, and should have quite a bit of room for the upper link mounting points. Will it be worth building some adjustment into the top brackets, and making the top links adjustable as well? On one of the rock crawler messageboards, pirate4x4 someone has a 3 and 4 link calculator to help guys get a good starting point on building their setups, wish I could use that for this! Could I? Im wanting to make sure this wont turn out to be a horrible handling truck, just a good all around-er.

What material should I build the links out of? I was thinking some square tubing for the lowers, making it easier to mount bag brackets to. Any suggestions on what size DOM I should lean towards since Ill be planning on throwing a trailer/jeep off the back of this thing? I see suicidedoors sells some bushing with some MASSIVE 1 1/8 studs welded on them. That seems like a whole lot of overkill for something like this. Will a 3/4 stud be stout enough for me? That will make it easier to get link tubing for as well. Speaking of, how long is too long for links? This is a longbed truck, so I could go as far forward as the back of the cab, what should I shoot for?

Anything else you guys can think of? Im going to order all of my bag stuff next week, and try to get everything situated to where I can tear the truck down and start on it ASAP.

And sorry for all the questions guys, this will be the FIRST 4 link project Ive ever tried, and just want to know as much about what Im getting into as I can. I cant help but pick some brains as there seems to be a few pretty sharp guys on this board.

Kyle

[ElkyRacer]

Wow, amazing what a few hours of searching sites can do. Ive just about found answers to every question I posted above! Searching pays off for sure! Now the only thing Im still left looking for is suggestions on what materials to use. More searching will probably uncover this as well!