Front 3 link; 2nd opinion

[rondo]

3 link defined

Milner,
It's a 3 link, thanks! If it was a radius arm setup then i would have said radius arm I know where you're coming from, and i'm not sure there is a definite consensus on the definition. My junker has two lower arms, needs 1 upper arm to locate the axle fore and aft and a track bar or panhard to keep it located side to side. True 4 link? In my mind the track bar is never included as a link. 'head hurts now'.

 

[rondo]

guns and beer ............
im in if you dont mind another tagging along?
Dwayne
im in tooele already

Well these guys can't make it out this weekend, but i don't mind if you want to stop by. Is your sammi red? I like that thing A LOT! Looks like a lot of fun to wheel in.

Right now on my project i'm torn as to where to put the upper link. I recall the fellahs at BHR said it doesn't matter too much, all it does is locate the axle but i'm still unsure. If i fit it to the inside of the frame then i've got to reroute my exhaust and maybe screw with the crossmember. If i put it on the drivers side then there's a bit more room but I didn't figure on locating the arm to the top of the pumpkin, so i think i'd want a bridge built as the axle is already fully built and i don't want to weld the bracket to the center chunk.

Right now i have it mocked up on the passenger side outside of the frame. This looks really good actually and requires the least modification, and i saw the rigs at moab outpost doing this with their jeep kits. The only thing is the upper link will have very little triangulation. So does that piece of it matter? I do read a lot and search a lot and some toyota weenies were saying the 3 link upper should be close to the center of the axle I've seen a lot of rigs in my life and have been wheeling for over 20 years and i've never seen that??

 

[rondo]

Yeah Ron, these guys will do a good job of recommending ways to properly complete your project. Its great they are willing to make the trip out there!

Thx Von, you and BHR have been a great help on this project.

 

[kake]

3 link

Milner,
It's a 3 link, thanks! If it was a radius arm setup then i would have said radius arm I know where you're coming from, and i'm not sure there is a definite consensus on the definition. My junker has two lower arms, needs 1 upper arm to locate the axle fore and aft and a track bar or panhard to keep it located side to side. True 4 link? In my mind the track bar is never included as a link. 'head hurts now'.

This is exactly what I had pictured in when you described, as I don't count the Panhard/track bar either. I believe that they say you need to locate it as close to the middle to counter act the forces I was refering to in my first post. What you will notice is that under stress the side that doesn't have the upper link will tend to pivot a little bit and even creep forward and back. Again, I have used this setup on a competition rock crawler and it worked fine--great even! However, on the pavement under stopping and excelleration(4wd) you may notice your vehicle pull one way or the other. Combined with hard core rock crawling your parts will wear and loosen up faster, creating even worse road manners. The last thing to consider is strength. What will happen if your ONE upper link fails? Maybe consider two smaller upper links if possible. They don't need to be super long necessarily. I know there are many 3 link enthusiasts out there, but when all considered and it can be done, the more links to control your front axle the better. It will obviously be a choice of street or offroad? I believe you can have both but it isn't easy.

 

[RockMonkey]

What will happen if your ONE upper link fails?

When his one upper link fails, the same thing happens when one of my radius arms fail, or when one of my triangulated links (upper or lower) fail. He'll lose control of the axle position. There's no redundency built into any popular linked suspension system. All it takes is for any one of the links to fail, and your axle is no longer controllably located under the vehicle.

Ideally, you would want the link as close to the center of the axle as possible. Realistically, it's going to be on one side or the other, because you have an engine in your crawler. You will want to make sure the axle is trussed to prevent it from twisting. I spun the tube on my front 60 with this type of suspension.

You do not want this link to be triangulated. The purpose of triangulating links is to give the link system the ability to position the axle side-to-side. In this suspension you'll have a track bar for that job, and you don't want it to fight another link moving in a different arc. One of them will win, but you will definitely lose.

If you put the link on the outside of the frame, will you have room to turn your tires lock-to-lock throughout the range of the suspension cycle without the tire hitting the upper link?

 

[Vonski]

When his one upper link fails, the same thing happens when one of my radius arms fail, or when one of my triangulated links (upper or lower) fail. He'll lose control of the axle position. There's no redundency built into any popular linked suspension system. All it takes is for any one of the links to fail, and your axle is no longer controllably located under the vehicle.

This is an excellent statement. But just to be clear, Braden's intention is not to concern those of you that currently run the common 3-link front suspension design, or predict any sort of eventual failure.

If not built properly, you run the risk of "axle location" failure of some kind, no matter what design you are running. I am confident in the use of single upper links in front suspensions, but beefy components should be used.

So, if you doubt the strength of your welding, bracketry, links, or components in regards to a single upper, maybe a second one is appropriate. OEM Jeep engineered their suspensions that way, and many are glad once the bracketry starts ripping off.

In all fairness, Jeep never planned on people abusing their equipment like we all do...

 

[cumminram]

Good point, I run a hydraboost brake set up on mine also, at first I was kind of worried the single third link wouldnt be able to take that kind of braking pressure. Ive been running it that way for over 2 yrs now without any failure

 

[kake]

Exactly

When his one upper link fails, the same thing happens when one of my radius arms fail, or when one of my triangulated links (upper or lower) fail. He'll lose control of the axle position. There's no redundency built into any popular linked suspension system. All it takes is for any one of the links to fail, and your axle is no longer controllably located under the vehicle.

Ideally, you would want the link as close to the center of the axle as possible. Realistically, it's going to be on one side or the other, because you have an engine in your crawler. You will want to make sure the axle is trussed to prevent it from twisting. I spun the tube on my front 60 with this type of suspension.

You do not want this link to be triangulated. The purpose of triangulating links is to give the link system the ability to position the axle side-to-side. In this suspension you'll have a track bar for that job, and you don't want it to fight another link moving in a different arc. One of them will win, but you will definitely lose.

If you put the link on the outside of the frame, will you have room to turn your tires lock-to-lock throughout the range of the suspension cycle without the tire hitting the upper link?

You are no fun. I wanted to leave something up to his imagination. Ha ha.

 

[RockMonkey]

You are no fun. I wanted to leave something up to his imagination. Ha ha.

You mean like the inevitable drive shaft and coilover/air shock carngage that will result? I don't even like to imagine that stuff.

FWIW the buggy in my avitar has two uppers and one lower in the front. I never had any problems, other than a broken joint, and spun axle tube. Neither resulted in any damage to other components.

 

[rondo]

clarification

When his one upper link fails, the same thing happens when one of my radius arms fail, or when one of my triangulated links (upper or lower) fail. He'll lose control of the axle position. There's no redundency built into any popular linked suspension system. All it takes is for any one of the links to fail, and your axle is no longer controllably located under the vehicle.

Ideally, you would want the link as close to the center of the axle as possible. Realistically, it's going to be on one side or the other, because you have an engine in your crawler. You will want to make sure the axle is trussed to prevent it from twisting. I spun the tube on my front 60 with this type of suspension.

You do not want this link to be triangulated. The purpose of triangulating links is to give the link system the ability to position the axle side-to-side. In this suspension you'll have a track bar for that job, and you don't want it to fight another link moving in a different arc. One of them will win, but you will definitely lose.

Mr. Kake, thanks for mentoring me but with the weird shape of the Frontier frame and the full width axle, i'm thinking the tires will be okay lock to lock. If they are somewhat limited that's okay because this thing need not turn like a car. Thing is i initially figured the upper link would triangulate to some degree toward to middle of the tube (about 1/4 of the way) and that would help keep the tires out of it.

As for hard core crawling, it isn't its primary purpose however i want it to survive for the occasional beating

Okay Rockmonkey, at 1st glance the statements appear to contradict, only because i'm a bit slow today, but i think i know what you are saying. upper third link need not triangulate because it has a track bar. Then what i read about yotas with the upper 3rd link center of the axle means they don't have a track bar? I know on most of the setups i've seen the upper 3rd link is triangulated a little bit, but perhaps only to clear all the other 'stuff' on the pumpkin.

Von: no worries on failure, because the double sleeved tube i got from BHR is plenty strong. Thx!

The welding will be done by my pal who is a professional. Taking no chances there.

With the upper link size, i'm confused. I've seen two setups recently, one done at Mt. Logan, and another by Rock Logic. Their upper links were quite small compared to the beef of the lowers. Seems the thinking was they didn't have to be as strong? I guess that's a philosophical discussion. Mine are made out of the same material and heims, and i think i can even make it the same length in front, so i'll need only carry one spare. I've seen equal length arms on the front of rigs, but on the back i understand the links are often made different lengths top to bottom. Not sure we want to get into the whole link geometry discussion.

 

[I Lean]

Upper links CAN be smaller, since they don't see the loading the lowers can. (from landing on stuff...)

Bigger links aren't bad ever, but they may cost extra or weigh more, neither of which is a deal-breaker.

If your upper link is angled some, it won't affect a much.

 

[abhaulr1]

No i dont have the red one. mine is black. let me know if you need any help or an extra hand. Dwayne

 

[rockdog]

When his one upper link fails, the same thing happens when one of my radius arms fail, or when one of my triangulated links (upper or lower) fail. He'll lose control of the axle position. There's no redundency built into any popular linked suspension system. All it takes is for any one of the links to fail, and your axle is no longer controllably located under the vehicle.

Ideally, you would want the link as close to the center of the axle as possible. Realistically, it's going to be on one side or the other, because you have an engine in your crawler. You will want to make sure the axle is trussed to prevent it from twisting. I spun the tube on my front 60 with this type of suspension.

You do not want this link to be triangulated. The purpose of triangulating links is to give the link system the ability to position the axle side-to-side. In this suspension you'll have a track bar for that job, and you don't want it to fight another link moving in a different arc. One of them will win, but you will definitely lose.

If you put the link on the outside of the frame, will you have room to turn your tires lock-to-lock throughout the range of the suspension cycle without the tire hitting the upper link?

I agree with everything Braden says here. This is the setup I have on my toy. It works great. If I were to drive it on the street I'd add a sway bar. Locate the top link where it fits the best, with the least interference.