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Unread 01-06-2012, 12:17 PM   #31
RaggedOleMan
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Quote:
Originally Posted by Imped View Post
Triangulated lowers will converge at the frame end and will always be wide at the axle. Triangulated uppers will always converge at the axle. I've never seen it done another way, likely due to some funky numbers that would cause.....especially with converging lowers below the diff, where you'd also experience a huge loss of clearance.
IMPED; The carpenter/contractor in me understands the significance of diagonal bracing, and lateral restraints. That said, does the triangulation of the rear uppers result in enough lateral stability, such that the rear trac-bar can be eliminated?

Additionally, when a 3-link, or 4-link is discussed, are the number of links consistent with the number of rod ends? If so, then if the trac-bar would add two additional "links". If that's a true statement, then a stock Tj, with the trac-bar is essentially a 6-link? Am I understanding this correctly?

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Unread 01-06-2012, 01:37 PM   #32
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Originally Posted by RaggedOleMan View Post
IMPED; The carpenter/contractor in me understands the significance of diagonal bracing, and lateral restraints. That said, does the triangulation of the rear uppers result in enough lateral stability, such that the rear trac-bar can be eliminated?
Of course. Triangulated setups are above and beyond the most common rear link setup on offroad rigs. In order to properly hold the axle in place, you need to have a minimum of 40 degrees of triangulation in the system, whether it be the uppers or lowers. For example, the Poly brackets triangulate the lowers at 10 degrees and the uppers at 25 degrees. So if you drew imaginary lines on the lowers to their convergence point, that angle would be 20 degrees. The uppers would be 50 degrees. It's doing the same job a track bar does. If I jack the axle up off the ground and go to push on it from the driver's side tire, it won't budge--the passenger upper and driver's lower would have to shorten and the driver upper and passenger lower would have to lengthen. So as long as you don't use spaghetti noodles as links, your axle won't go anywhere.
Quote:
Originally Posted by RaggedOleMan View Post
Additionally, when a 3-link, or 4-link is discussed, are the number of links consistent with the number of rod ends? If so, then if the trac-bar would add two additional "links". If that's a true statement, then a stock Tj, with the trac-bar is essentially a 6-link? Am I understanding this correctly?
The word "link" refers to an arm, or bar. A control arm is a link, a track bar is a link. The ends have nothing to do with it. A system using 2 lowers and 2 uppers to constrain the axle is a 4 link. A front suspension using 2 lowers, one upper and a track bar is either a 4 link or 3 link + panhard (another word for a track bar). On that note, the track bar is required up front in that setup for lateral constraint because there's only one upper--that arm is doing one thing and that's not allowing the axle to rotate around itself. Without a second upper, it's not performing any type of lateral constraint because it's missing the other side of the triangle. The track bar is also needed if you're running any steering setup that uses linkage (aka anything but full hydro). But that's another subject.
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Unread 01-06-2012, 03:22 PM   #33
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Originally Posted by Imped View Post
Of course. Triangulated setups are above and beyond the most common rear link setup on offroad rigs. In order to properly hold the axle in place, you need to have a minimum of 40 degrees of triangulation in the system, whether it be the uppers or lowers. For example, the Poly brackets triangulate the lowers at 10 degrees and the uppers at 25 degrees. So if you drew imaginary lines on the lowers to their convergence point, that angle would be 20 degrees. The uppers would be 50 degrees. It's doing the same job a track bar does. If I jack the axle up off the ground and go to push on it from the driver's side tire, it won't budge--the passenger upper and driver's lower would have to shorten and the driver upper and passenger lower would have to lengthen. So as long as you don't use spaghetti noodles as links, your axle won't go anywhere.

The word "link" refers to an arm, or bar. A control arm is a link, a track bar is a link. The ends have nothing to do with it. A system using 2 lowers and 2 uppers to constrain the axle is a 4 link. A front suspension using 2 lowers, one upper and a track bar is either a 4 link or 3 link + panhard .
Thanks for taking the time, and employing the patience to explain it, Imped. So...it's now my understanding that...

With a triangulated 4 link in the rear, and in the absence of a panhard/trac-bar, the forces visited up the uppers (and lowers) would be considerably greater, as opposed to having a panhard/trac-bar in the equation. In addition, the length of the uppers and the lowers is now increased, which indicates the forces (leverage) visited upon them are considerably greater. Thus, those arms & joints need to be strong enough to be able to handle the additional loads, and that's why one doesn't use "noodles" as links...got it...and...

When a 3-link system is used, the panhard/trac-bar is required, makes sense. Are their exceptions to that?

Ah-ha moment...among the advantages of a 4-link in the front, is the additional real estate available because of the absence of the panhard/trac-bar, for say beefier steering components...
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Unread 01-06-2012, 03:55 PM   #34
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Originally Posted by RaggedOleMan View Post
Ah-ha moment...among the advantages of a 4-link in the front, is the additional real estate available because of the absence of the panhard/trac-bar, for say beefier steering components...
I believe you missed something. You absolutely can not triangulate the front and ditch the track bar if you're using y-link, inverted y, t-link, or almost any type of link type steering. It may be possible with an exceptionally complicated and very carefully engineered K-link set up, be we won't go there.

Fro the purposes of most normal link style steering application you need a track bar that is roughly parallel to the drag link. This is so the axle moves side to side as it goes up and down the same amount that the steering linkage (namely the drag link) does. Other wise the axle moving up and down during suspension cycling would cause your tires to steer left and right on their own (bump steer).

I have seen bump steer so bad that turning the steering back and forth with the axle level and the Jeep sitting still causes the front of the Jeep to dip side to side. The steering literally fought the suspension so bad it pulled one side of the Jeep down and pushed the other up.

However, if you went with fully hydraulic steering (no physical linkage) you could triangulate the front and ditch the track bar. I hope that helped and didn't confuse you worse.
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Unread 01-06-2012, 04:11 PM   #35
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Originally Posted by NotURMailman View Post
I believe you missed something. You absolutely can not triangulate the front and ditch the track bar if you're using y-link, inverted y, t-link, or almost any type of link type steering. It may be possible with an exceptionally complicated and very carefully engineered K-link set up, be we won't go there.

Fro the purposes of most normal link style steering application you need a track bar that is roughly parallel to the drag link. This is so the axle moves side to side as it goes up and down the same amount that the steering linkage (namely the drag link) does. Other wise the axle moving up and down during suspension cycling would cause your tires to steer left and right on their own (bump steer).

I have seen bump steer so bad that turning the steering back and forth with the axle level and the Jeep sitting still causes the front of the Jeep to dip side to side. The steering literally fought the suspension so bad it pulled one side of the Jeep down and pushed the other up.

However, if you went with fully hydraulic steering (no physical linkage) you could triangulate the front and ditch the track bar. I hope that helped and didn't confuse you worse.
Well said!
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Unread 01-06-2012, 04:14 PM   #36
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I am anxious to see how well it performs. I am going to pm you for details
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Unread 01-06-2012, 04:33 PM   #37
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Originally Posted by NotURMailman View Post
I believe you missed something. You absolutely can not triangulate the front and ditch the track bar if you're using y-link, inverted y, t-link, or almost any type of link type steering. It may be possible with an exceptionally complicated and very carefully engineered K-link set up, be we won't go there.
Yeah, I knew that...yup, knew it all the time. What? You think I was serious? Ah man...I missed something alright! The truth is I didn't have a friggin' clue. Not a clue. Humility, where would we be without it, eh?

Okay, I'll stay out of this thread now so all the grown-ups can talk...
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Unread 01-06-2012, 04:35 PM   #38
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Originally Posted by RaggedOleMan View Post
Yeah, I knew that...yup, knew it all the time. What? You think I was serious? Ah man...I missed something alright! The truth is I didn't have a friggin' clue. Not a clue. Humility, where would we be without it, eh?

Okay, I'll stay out of this thread now so all the grown-ups can talk...
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Unread 01-06-2012, 06:24 PM   #39
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Originally Posted by RaggedOleMan

Yeah, I knew that...yup, knew it all the time. What? You think I was serious? Ah man...I missed something alright! The truth is I didn't have a friggin' clue. Not a clue. Humility, where would we be without it, eh?

Okay, I'll stay out of this thread now so all the grown-ups can talk...
No need to stay out. That's what forums are for. I was just trying to help you get it all straight.
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Unread 01-06-2012, 09:16 PM   #40
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Good info Thanks for sharing
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Unread 01-06-2012, 11:09 PM   #41
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I'd like to get in on the discussion if'n you don't mind.

I'm a little concerned about having the upper and lower relying on a single point at the frame...



That's a lot of stress for two 4 inch welds.

And then onto better things... I commend you for the rather difficult weld angles. You did good.

Are you ever going to eliminate the sway bar? It seems the reason for the triangulation is for articulation. I drive mine daily without a rear sway bar, and it handles pretty good in the corners.

Personally I would like to install the Teraflex long arm, but I don't like the quality of the axle bridge. Maybe a question for imped, but would another brand of bridge work with the t-flex without having to work on the arms?
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Unread 01-06-2012, 11:20 PM   #42
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Originally Posted by Yams View Post
I'd like to get in on the discussion if'n you don't mind.

I'm a little concerned about having the upper and lower relying on a single point at the frame...

That's a lot of stress for two 4 inch welds.
If the welds are good, which they look fine, it's not an issue. Lots of guys using the same link brackets to swap 1 ton axles and run 40s. Those brackets are up to the task.


Quote:
Are you ever going to eliminate the sway bar? It seems the reason for the triangulation is for articulation. I drive mine daily without a rear sway bar, and it handles pretty good in the corners.
Eliminating the rear sway bar does more harm than good both on the road and off the road. The rear sway bar doesn't limit "useful" articulation but it does help control body roll and stability in off-camber situations
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Unread 01-07-2012, 12:06 AM   #43
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Quote:
Originally Posted by Yams View Post
I'd like to get in on the discussion if'n you don't mind.

I'm a little concerned about having the upper and lower relying on a single point at the frame...



That's a lot of stress for two 4 inch welds.

And then onto better things... I commend you for the rather difficult weld angles. You did good.

Are you ever going to eliminate the sway bar? It seems the reason for the triangulation is for articulation. I drive mine daily without a rear sway bar, and it handles pretty good in the corners.

Personally I would like to install the Teraflex long arm, but I don't like the quality of the axle bridge. Maybe a question for imped, but would another brand of bridge work with the t-flex without having to work on the arms?
I had to use a mirror on mine, mirrors don't last long.
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Unread 01-07-2012, 12:40 AM   #44
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Quote:
Originally Posted by Yams View Post
I'd like to get in on the discussion if'n you don't mind.

I'm a little concerned about having the upper and lower relying on a single point at the frame...



That's a lot of stress for two 4 inch welds.

And then onto better things... I commend you for the rather difficult weld angles. You did good.

Are you ever going to eliminate the sway bar? It seems the reason for the triangulation is for articulation. I drive mine daily without a rear sway bar, and it handles pretty good in the corners.

Personally I would like to install the Teraflex long arm, but I don't like the quality of the axle bridge. Maybe a question for imped, but would another brand of bridge work with the t-flex without having to work on the arms?

I only wanted to quote the part where you said "That's a lot of stress for two 4 inch welds."

But I don't know how.

So yeah, that isn't two 4 inch welds. Those brackets make a C or a saddle and slide onto the frame from the inboard side of the frame. They wrap around the top of the frame and bottom of the frame. There's about 28" of weld holding that bracket on. Not to mention a couple plug welds on each side just for fun.

And thanks everyone for the compliments on the welds. I'm somewhat pround of them myself. They make me happy.
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Unread 01-07-2012, 12:45 AM   #45
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And as for the rear sway bar, I know what you're saying, but I've read countless times where Mr. Blaine (The Jeep Messiah) and Imped have proclaimed the need for sway bars front and rear. Even a few places where they have said the stock rear sway bar is perfectly fine for most situations even though at first glance, it appears rather spindly. So insted of even messing with it, I left it on. Plus, I really want to retain all the parts of the stock Jeep that actually work. As opposed to just arbitrarily ditching perfectly good stock components. I also pride myself on having kept the emergency brake and all its functionality even though it was a little bit of a pain with the new hardware in the way. It's not quite where I want it yet (The whole jeep) but it's getting there.
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