So as many of you who follow me on Instagram know, I recently redid my rear suspension setup and converted it to a 3 link. So before I get into the tech portion here's a little background on the project, why I decided to go this route, and what my goals for it were. If you don't like reading then this thread won't be for you, there's a lot of info.
So I do not run sway bars on my truck, I snapped the rear one in half and the front originally had disconnects but they were a pain in the ass to hook up anytime it wasn't totally dry and when they were hooked up they always rattled and clunked. As a result of the no sway bars I had a ton of body roll, so much so that I was consistently putting a tire in the air when I was going around corners and driving mountain passes were downright scary. So there's issue number one, too much body roll
Issue number 2, terrible geometry and roll steer. I only have about 3 inches of lift on my truck in the rear but even with a relatively small amount of lift, it was enough to really screw with the geometry. With my 10 inch stroke shocks and roughly 17 inches of articulation in the rear when the axle fully flexes the axle would be pulled so far out of alignment by the giant amount of roll steer that my tire that was being stuffed would be jammed almost totally into the rear of the wheel well and the drooped tire would be pulled forward and basically under my slider. Sound familiar? I'm sure it does. This was also really present when I was driving especially on the highway and amplified by the excessive body roll, anytime I would go through a turn at speed I could feel the rear end shift and grab forcing me into the turn almost like rear steer. Doesn't sound that bad but sitting in the drivers seat was super sketchy.
So issue three, the rear links. Late last year I swapped out my lower control arm bushings in favor of SPC x axis flex joints. I did this because they were sealed and low maintenance. Well, this proved to be a mistake. By July of this year they were starting to wear out and on a big trip in Colorado about a mile into Engineer pass the races completely failed causing a significant amount of slop and a huge clunk anytime I hit a bump in the road.
So if you're following along Ive got 3 major issues with my rear suspension and it was only getting worse. Late July I was looking at getting it fixed and at the time Josh of 530 motorsports was running a special on his solid aluminum links that I decided to get in on. As luck would have it I ran chinamans gulch the day after ordering the links and did this.
IMAG0274 by Phoenix Black, on Flickr
So at this point replacing the rear mounts is a must since the mount had been so smashed and mangled over the years that I couldn't get the joints out. Well if I'm going to replace the mounts I might as well gain some clearance, but to do that I have to rework all the geometry. Enter the 3 link. I choose to go with a 3 link because I do not plan on running the f150 fuel tank for a few reasons but mostly due to the fact it is kind of a pain to make work with the stock fuel gauge and just adds a potential point of failure on the trail. I've learned to wheel with the stock tank and it has proven to actually be helpful when snow wheeling due to the floatation. After talking with @AssBurns and bouncing some ideas off him I started playing around with the 3 link calculator.
First was measuring the stock setup to get a baseline and here is where it measured out to be
Screenshot (5) by Phoenix Black, on Flickr
As you can see the geometry is pretty shitty, the roll axis angle in particular, 10 degrees is incredibly high, and that's only with a 3 inch lift!
So after spending a lot of time under the truck measuring what was feasible to change and with an overall goal of decreasing roll steer and body roll I settled on this design that moves the lower frame mounts up and forward 1 inch, the lower axle mounts up and forward 1 inch. and the frame side upper down and forward 1.5 inches.
Screenshot (6) by Phoenix Black, on Flickr
This provided much less roll steer, and also got the anti-squat back into a more desirable range.
So onto the fabrication side of things...
First up was correcting the panhard, as we all know the panhard geometry gets way out of wack even with a small lift. @eimkeith makes a great kit to fix this, but in my case, I didnt want to use a drop bracket as it lowers the roll center slightly which increases body roll. I also knew that with my extended @Plastics Guy bumps I had the room to correct the height by only lifting the axle side mount, by 2.5 inches to be exact.
By doing this I accomplished two things, first I moved the roll center up by roughly an inch which makes a huge difference in the amount of body roll the truck has because it shortens the distance between the roll center and the center of gravity which I have estimated to by roughly 36 inches on my truck. The second thing this accomplished was leveling the bar. This is super important because it puts the bar back at the longest point at ride height. This measurement of the peak arc width is the saggita. The sagitta is the vertical line from the midpoint of the chord to the arc itself. It is a measure of the 'height' of the arc. The length of the chord, sagittaand radius of the arc are inter-related, and if you know any two you can calculate the third. Thats the official definition for those who care. But its also what causes the "dog wag" many experience after a lift, since the bar isnt level the arc it travels in is larger causing the vehicle to shift or "wag" side to side
In addition to raising the bar mount I extended it by an inch to get the axle perfectly centered. This was more for
Here's a really good video that explains the panhard system really well and is what I used as a guid for setting mine up
Here's my raised bracket and extended bar
IMG_0163 by Phoenix Black, on Flickr
IMAG0284 by Phoenix Black, on Flickr
I later filled that gap in with weld and ground smooth. The solid bar inside also extends 6 inches in either way, rest assured it is plenty strong.
So I do not run sway bars on my truck, I snapped the rear one in half and the front originally had disconnects but they were a pain in the ass to hook up anytime it wasn't totally dry and when they were hooked up they always rattled and clunked. As a result of the no sway bars I had a ton of body roll, so much so that I was consistently putting a tire in the air when I was going around corners and driving mountain passes were downright scary. So there's issue number one, too much body roll
Issue number 2, terrible geometry and roll steer. I only have about 3 inches of lift on my truck in the rear but even with a relatively small amount of lift, it was enough to really screw with the geometry. With my 10 inch stroke shocks and roughly 17 inches of articulation in the rear when the axle fully flexes the axle would be pulled so far out of alignment by the giant amount of roll steer that my tire that was being stuffed would be jammed almost totally into the rear of the wheel well and the drooped tire would be pulled forward and basically under my slider. Sound familiar? I'm sure it does. This was also really present when I was driving especially on the highway and amplified by the excessive body roll, anytime I would go through a turn at speed I could feel the rear end shift and grab forcing me into the turn almost like rear steer. Doesn't sound that bad but sitting in the drivers seat was super sketchy.
So issue three, the rear links. Late last year I swapped out my lower control arm bushings in favor of SPC x axis flex joints. I did this because they were sealed and low maintenance. Well, this proved to be a mistake. By July of this year they were starting to wear out and on a big trip in Colorado about a mile into Engineer pass the races completely failed causing a significant amount of slop and a huge clunk anytime I hit a bump in the road.
So if you're following along Ive got 3 major issues with my rear suspension and it was only getting worse. Late July I was looking at getting it fixed and at the time Josh of 530 motorsports was running a special on his solid aluminum links that I decided to get in on. As luck would have it I ran chinamans gulch the day after ordering the links and did this.
IMAG0274 by Phoenix Black, on Flickr
So at this point replacing the rear mounts is a must since the mount had been so smashed and mangled over the years that I couldn't get the joints out. Well if I'm going to replace the mounts I might as well gain some clearance, but to do that I have to rework all the geometry. Enter the 3 link. I choose to go with a 3 link because I do not plan on running the f150 fuel tank for a few reasons but mostly due to the fact it is kind of a pain to make work with the stock fuel gauge and just adds a potential point of failure on the trail. I've learned to wheel with the stock tank and it has proven to actually be helpful when snow wheeling due to the floatation. After talking with @AssBurns and bouncing some ideas off him I started playing around with the 3 link calculator.
First was measuring the stock setup to get a baseline and here is where it measured out to be
Screenshot (5) by Phoenix Black, on Flickr
As you can see the geometry is pretty shitty, the roll axis angle in particular, 10 degrees is incredibly high, and that's only with a 3 inch lift!
So after spending a lot of time under the truck measuring what was feasible to change and with an overall goal of decreasing roll steer and body roll I settled on this design that moves the lower frame mounts up and forward 1 inch, the lower axle mounts up and forward 1 inch. and the frame side upper down and forward 1.5 inches.
Screenshot (6) by Phoenix Black, on Flickr
This provided much less roll steer, and also got the anti-squat back into a more desirable range.
So onto the fabrication side of things...
First up was correcting the panhard, as we all know the panhard geometry gets way out of wack even with a small lift. @eimkeith makes a great kit to fix this, but in my case, I didnt want to use a drop bracket as it lowers the roll center slightly which increases body roll. I also knew that with my extended @Plastics Guy bumps I had the room to correct the height by only lifting the axle side mount, by 2.5 inches to be exact.
By doing this I accomplished two things, first I moved the roll center up by roughly an inch which makes a huge difference in the amount of body roll the truck has because it shortens the distance between the roll center and the center of gravity which I have estimated to by roughly 36 inches on my truck. The second thing this accomplished was leveling the bar. This is super important because it puts the bar back at the longest point at ride height. This measurement of the peak arc width is the saggita. The sagitta is the vertical line from the midpoint of the chord to the arc itself. It is a measure of the 'height' of the arc. The length of the chord, sagittaand radius of the arc are inter-related, and if you know any two you can calculate the third. Thats the official definition for those who care. But its also what causes the "dog wag" many experience after a lift, since the bar isnt level the arc it travels in is larger causing the vehicle to shift or "wag" side to side
In addition to raising the bar mount I extended it by an inch to get the axle perfectly centered. This was more for
Here's a really good video that explains the panhard system really well and is what I used as a guid for setting mine up
Here's my raised bracket and extended bar
IMG_0163 by Phoenix Black, on Flickr
IMAG0284 by Phoenix Black, on Flickr
I later filled that gap in with weld and ground smooth. The solid bar inside also extends 6 inches in either way, rest assured it is plenty strong.
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