Dave Kishpaugh's (Jeep West) geometry correction brackets are now available

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Body roll is a function of the roll center and not the anti-squat. There is more roll with a triangulated four link (like the mid arm referenced) then with a four link with a pan hard. Without the panhard, when the body rolls all the load goes into the springs/shocks/sway bar, with the panhard it will also go into the springs/shocks/sway bar AND the panhard.
Which is why in some situations the brackets could be better than a mid arm. Which is also why you can't make a blanket statement that one is better than the other. Each has their trade offs. You need to kno what purpose are you building for?

EDIT: Unless you are able to adjust the roll center of the 4 link by where you mounts are located. Which does seem reasonable to me. Although I suspect that again comes with trade offs. But I've never designed a suspension.
 
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Yes thats what I was meaning to say, but back to redrilling the lowers, would it be possible to simply redrill the lowers just by a small amount to reduce AS(using a calc to get wanted #s) or would it not be worth it
Just spit balling here, but maybe it has to do with keeping the upper and lower mounts equal within the center line of the axle. Drop only the lower mount and you are unequal with the center line of the axle tube?
 
Just spit balling here, but maybe it has to do with keeping the upper and lower mounts equal within the center line of the axle. Drop only the lower mount and you are unequal with the center line of the axle tube?
Im talking about redrilling the frame side, not the axle side, so I dont think it would be a problem
 
This why I don’t build suspension packages. It is difficult to get right. Especially for the guy who doesn’t do them often. You have to know how changing one thing effects all the others. Trial and error would take years to figure out what guys who build often already know.
Mon. i should be callin Tom Wood and ordering my new rear driveshaft at 31.5" long, if that gives you any idea of how much i changed things.

Was the body roll issue with the mid arms due to antisquat or lack of track bar? (Or a by product longer arms)
not sure i've not had any testing yet, @jjvw could answer that maybe.

to take a stab at it. i'd look more at the triangulation and the uppers being centrally located. and up front the single twig. it's not gonna hold like double outriggers, but that's part of the preference, easier articulation.

longer links is the byproduct of link mounting location choices, but they do have some benefits.
 
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On a side note, the other reason I’m interested In These brackets is they should help me be able to move the rear axle back at ride height. With my tcase doubler project I look to be loosing 1-1.5” of d line length.
 
How is roll center effected by pan hard bar angle?
I just listened to the video. (Kinda, I listened while at work) I don't think the angle of the pan hard bar is the issue per se. The issue is where is the height of centerline on the pan hard bar. That is your roll center. But that does mean that the higher you can get the bar the higher your roll center. The highest you can go on both sides is into the tub, at which point the bar is horizontal and you have a very high roll center. On the other hand, lowering the track bar on the frame side will also make it horizontal, but at a much lower point, so you will have a lower roll center. At least that is how I understand it. But I'm still learning.
 
How is roll center effected by pan hard bar angle?
angle effects axle motion. not roll center. this is why we raise the TB mount to cheat some of that back. you could go up = to the amount of lift you added if that did not effect your top end travel expectations.

the center of your bar is your RC back there a standard TB riser does minimal to raise that.

but the easier solution is a stiffer sway. is this why the AR is on the old toy list for so many now?
 
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Which is why in some situations the brackets could be better than a mid arm. Which is also why you can't make a blanket statement that one is better than the other. Each has their trade offs. You need to kno what purpose are you building for?

EDIT: Unless you are able to adjust the roll center of the 4 link by where you mounts are located. Which does seem reasonable to me. Although I suspect that again comes with trade offs. But I've never designed a suspension.
You can sacrifice some roll center knowing that a sway bar and/or outbd shocks can make up for the body roll issue. I would rather focus on the AS and build a good four link that is going to move up and down and articulate properly with as much travel as possible without contacting the body or binding with some roll center being sacrificed. This is because the body roll can be accounted for by other methods (sway bar, coil overs, outbd shocks, etc...) while the AS, short travel, binding, etc... cannot be.
 
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angle effects axle motion. not roll center. this is why we raise the TB mount to cheat some of that back. you could go up = to the amount of lift you added if that did not effect your top end travel expectations.

the center of your bar is your RC back there a standard TB riser does minimal to raise that.

but the easier solution is a stiffer sway. is this why the AR is on the old toy list for so many now?

Look at what AEV did with the JK. They raised the rear track bar higher than the lift height to give it more stability than stock. They have some pretty impressive videos of how stable the JK handles on a test track with 35s. They also used geometry correction brackets up front. But maybe that shouldn't be surprising since the lead engineer on that project was the same guy who founded Nth Degree and developed the Handling Improvement Kit for the TJ that has come up in this thread as a predecessor to Daves brackets.

Since raising the track bar an inch on one end will only raise the roll center 1/2" in the middle, its hard to imagine it makes that much of a difference. But it worked well for AEV on the JK. I don't know.

A stiffer sway bar would make it more stable on the road. But like everything else, there is that trade off.

I thought the video make a good point about having too high of a roll center and how that can be a negative as well.
 
Since raising the track bar an inch on one end will only raise the roll center 1/2" in the middle, its hard to imagine it makes that much of a difference. But it worked well for AEV on the JK. I don't know.
I think someguysjeep, your and my posts are crossing and overlapping, I guess we are all typing at different speeds :)

someguy was stating that the pan hard angle affects how the axle travels. you want the axle to go up and down in as straight a line as possible. However, if you are connected to a bar (track bar) that swings on a radius, as it swings through that radius it will draw the axle closer or further away (push it left and right and/or tilt it). The flatter the bar the axle end is closer to a vertical tangent line, if the bar is angled, the tangent line is also angled. Someguy please correct me if that is not what you were referring.
 
Look at what AEV did with the JK. They raised the rear track bar higher than the lift height to give it more stability than stock. They have some pretty impressive videos of how stable the JK handles on a test track with 35s. They also used geometry correction brackets up front. But maybe that shouldn't be surprising since the lead engineer on that project was the same guy who founded Nth Degree and developed the Handling Improvement Kit for the TJ that has come up in this thread as a predecessor to Daves brackets.

Since raising the track bar an inch on one end will only raise the roll center 1/2" in the middle, its hard to imagine it makes that much of a difference. But it worked well for AEV on the JK. I don't know.

A stiffer sway bar would make it more stable on the road. But like everything else, there is that trade off.

I thought the video make a good point about having too high of a roll center and how that can be a negative as well.
so much of this is where on the scale are you aiming for what you wanna do, or what you wanna make better.
 
I have never seen anyone make a case for mid arms being better on the road. In fact my understanding is the exact opposite. My understanding is that most mid arms are a 4 link system with no tracbar and will actually have more body roll on the road than short arms. I thought jjvw said something earlier in the thread about this. (I'm just talking geometry here. Body roll can also be mitigated somewhat with dual rate springs and shocks.)

jjvw, can you give your input on how a midarm changes handling characteristics on the road. In particular body roll and handling dynamics.
Already did that here. I had an Antirock and 3.5" short arms before. After, it was a little different. If you are looking for it and know your Jeep very well, there is a very minor amount of added roll. That changed after the outboard and the rear shocks I put in. And every major change to the shocks and sway bars I have done since has only continued to improve the road handling. These were where the dramatic on road changes happened and all were all for the better.
 
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not sure i've not had any testing yet, @jjvw could answer that maybe.

to take a stab at it. i'd look more at the triangulation and the uppers being centrally located. and up front the single twig. it's not gonna hold like double outriggers, but that's part of the preference, easier articulation.

longer links is the byproduct of link mounting location choices, but they do have some benefits.

If one follows the logical progression, by the time you add the Savvy MA, the shocks and sway bars have already overshadowed whatever effects the MA has on the street. It will be largely invisible until you get on a tougher trail. If you want big improvements across the board, focus on the shocks.
 
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If one follows the logical progression, by the time you add the Savvy MA, the shocks and sway bars have already overshadowed whatever affects the MA has on the street. It will be largely invisible until you get on a tougher trail. If you want big improvements across the board, focus on the shocks.
Are you running the AR in the rear?
 
I think someguysjeep, your and my posts are crossing and overlapping, I guess we are all typing at different speeds :)

someguy was stating that the pan hard angle affects how the axle travels. you want the axle to go up and down in as straight a line as possible. However, if you are connected to a bar (track bar) that swings on a radius, as it swings through that radius it will draw the axle closer or further away (push it left and right and/or tilt it). The flatter the bar the axle end is closer to a vertical tangent line, if the bar is angled, the tangent line is also angled. Someguy please correct me if that is not what you were referring.
a crude flat vs angled sketch a same top end same travel distance.

2circle.PNG
 
it's a fair point. How often do LCA frame mounts present a clearanceissue on a shortarm where the mount is within the radius of the tire?
This is with a 35” tire. So it’s no really in the radius of the tire until 37”+. Which at that point you are in the realm of custom suspension anyway.

232A32AE-4F32-4F03-9A15-93CA4B63CE86.jpeg
 
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