Nth Degree Rear Lower Control Arm (LCA) Geometry Correction Template

I got out to ride 1/1 and it was the first time I never had wheel hop all day. I think I am definitely on the right track to better short arm suspension. I am going to try to get some good measurement on all the pick up points and see what the geometry looks like and what my next move is.

Correction on parts around $150 total

UCA mounts and track bar mount

https://www.barnes4wd.com/TJ-Rear-A...k-Bar-Brackets-DANA-60-AND-FORD-88_p_677.html
UCA mount extension

https://www.barnes4wd.com/Flat-Bottom-Link-Mount-Bracket-Pair_p_164.html

Shock mounts

https://www.rustysoffroad.com/rusty-s-straight-shock-mount-with-squared-end.html
 
I posted all of the Nth instructions last year. I also have the drill template. @mrblaine had some comments about how this worked compared to other suspension systems when we discussed this the last time. Tim
 
Brianj5600 said:
I got out to ride 1/1 and it was the first time I never had wheel hop all day. I think I am definitely on the right track to better short arm suspension. I am going to try to get some good measurement on all the pick up points and see what the geometry looks like and what my next move is.

Correction on parts around $150 total

UCA mounts and track bar mount

https://www.barnes4wd.com/TJ-Rear-A...k-Bar-Brackets-DANA-60-AND-FORD-88_p_677.html
UCA mount extension

https://www.barnes4wd.com/Flat-Bottom-Link-Mount-Bracket-Pair_p_164.html

Shock mounts

https://www.rustysoffroad.com/rusty-s-straight-shock-mount-with-squared-end.html
Click to expand...


That is awesome that it worked out good for you. Thanks for all the input and you posting your findings.



astjp2 said:
I posted all of the Nth instructions last year. I also have the drill template. @mrblaine had some comments about how this worked compared to other suspension systems when we discussed this the last time. Tim
Click to expand...

The instructions are here in this thread also and I have the drill template I'll loan to anyone who wants to use it.
 
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Just re-reading some of this stuff as I start to plan out the next phase of my build. I see a lot of conversation about the rear of the TJ getting geometry corrected, but what about the front? Is the juice not worth the squeeze? Or are people so hyper focused on climbing that they are forgetting about anti-dive geometry.

Probably should be it's own thread, but I thought I'd start here...
 
there are a few basic rules of link separation that apply to establish the AS/AD and IC.
what i can relate is the deeper you go into suspension geometry the more complicated it gets...you keep finding little things that influence the drive.

1st is this calculator everybody uses have a drive bias? how about a braking bias?

restoring what the factory had or trying to get close to it requires a different approach.

you could reestablish new axle link mount points to coincide with your lift height. (this will net you no more than factory up travel, ever)
or you can move the frame ends mounts away, to create the same effect.
the AS/AD and IC comes from where and in what relationship to each other these mount points are located.

and in the end, axle end link separation also plays a role in another reason why a 35" wheel is the limit on TJ axles.
 
unbelievable I have not seen this thread before.

The lower correction template is completely worthless without relocating the axle end of the upper control arms.

When used with a stinger, which is based on 3rd gen CAMARO rear suspension, it takes away the hop and allows a smooth, level take off.

The nth degree brackets require a little over 3" bumpstop extension to keep them off of the body under full compression.

I have developed "geometry correction" brackets over the last 8 years that were specifically for the short arm suspension. It takes away the bind point of the suspension in a full 12" travel range and operates on a 2" bumpstop extension without a body lift. These brackets also seve extremely well used with long and mid arm suspension links. They are the "cure" to rubicon express and metal cloak rear geometry issues.

Here is an example of the originals I made to bolt on, along with new brackets to be a weld on. I quickly improved them and now only make them as a weld on.

Anyone that has ever driven an nth degree short arm jeep or one of my builds with 2- 4" geometry correction lifts, knows they are nothing short of amazing.

20200713_192348.jpg


20200713_161741.jpg


20200608_220333.jpg


FB_IMG_1591630076945.jpg


20200419_141223.jpg
 
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jjvw said:
An outboard with better shocks will have a far greater overall improvement than messing with the arms. While the arm length will play a role in the positioning of the shock mounts and effect the amount of required bump stop extension, this should be treated as a separate project with a different set of goals.
Click to expand...

Raising the upper links and relocation of the lowers has a far greater overall improvement over any outbound shocks of any kind or tune. I learned this from experience after having installed hundreds of outboards. Then came the first geometry correction project which simply came about due to a busted bracket... hey, lets try this.

Outboards and sway bars are a bandaid on poor rear suspension geometry.
 
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David Kishpaugh said:
Raising the upper links and relocation of the lowers has a far greater overall improvement over any outbound shocks of any kind or tune. I learned this from experience after having installed hundreds of outboards. Then came the first geometry correction project which simply came about due to a busted bracket... hey, lets try this.

Outboards and sway bars are a bandaid on poor rear suspension geometry.
Click to expand...
this is the idea i had when i saw how the MC short arm operated.(like stilts).............why are we not just moving the axle brackets up to restore what we lifted away from. it's not a very popular idea, i was told there could be no gain in up travel due to the extended uppers, nobody does it
i always hear how good the stock suspension works but we all go right to jackin it up with crazy link angles. i'd like to try 1 myself and do all the changes at the axle end and see what it could produce for a travel range.
 
David Kishpaugh said:
unbelievable I have not seen this thread before.

The lower correction template is completely worthless without relocating the axle end of the upper control arms.

When used with a stinger, which is based on 3rd gen CAMARO rear suspension, it takes away the hop and allows a smooth, level take off.

The nth degree brackets require a little over 3" bumpstop extension to keep them off of the body under full compression.

I have developed "geometry correction" brackets over the last 8 years that were specifically for the short arm suspension. It takes away the bind point of the suspension in a full 12" travel range and operates on a 2" bumpstop extension without a body lift. These brackets also seve extremely well used with long and mid arm suspension links. They are the "cure" to rubicon express and metal cloak rear geometry issues.

Here is an example of the originals I made to bolt on, along with new brackets to be a weld on. I quickly improved them and now only make them as a weld on.

Anyone that has ever driven an nth degree short arm jeep or one of my builds with 2- 4" geometry correction lifts, knows they are nothing short of amazing.

View attachment 177401

View attachment 177402

View attachment 177404

View attachment 177405

View attachment 177406
Click to expand...
How much are the brackets?
 
someguysjeep said:
this is the idea i had when i saw how the MC short arm operated.(like stilts).............why are we not just moving the axle brackets up to restore what we lifted away from. it's not a very popular idea, i was told there could be no gain in up travel due to the extended uppers, nobody does it
i always hear how good the stock suspension works but we all go right to jackin it up with crazy link angles. i'd like to try 1 myself and do all the changes at the axle end and see what it could produce for a travel range.
Click to expand...

Isn't raising the uppers like that is going to put a lot of stress on the brackets? Wouldn't reducing the leverage at the lowers only add stress to raised uppers? We have examples of people bending 4 link trusses after similar changes when they raise the lowers for the purposes of creating ground clearance.
 
jjvw said:
Isn't raising the uppers like that is going to put a lot of stress on the brackets? Wouldn't reducing the leverage at the lowers only add stress to raised uppers? We have examples of people bending 4 link trusses after similar changes when they raise the lowers for the purposes of creating ground clearance.
Click to expand...
Raising the lowers will add stress to the upper. How much? Who knows. It will take someone smarter than me with a pretty powerful computer to figure that out.

Aren't there also examples of people bending and breaking factory mount locations too? Even without lift and huge articulation. My point is that its possible to bend/break anything. I'm not saying this is the end all, be all modification, but I also don't want to see this discussion devolve into another "Four inches of lift, Savvy, and Fox is the only right way to do things" discussion.
 
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Mike_H said:
Raising the lowers will add stress to the upper. How much? Who knows. It will take someone smarter than me with a pretty powerful computer to figure that out.

Aren't there also examples of people bending and breaking factory mount locations too? Even without lift and huge articulation. My point is that its possible to bend/break anything. I'm not saying this is the end all, be all modification, but I also don't want to see this discussion devolve into another "Four inches of lift, Savvy, and Fox is the only right way to do things" discussion.
Click to expand...

Ask yourself how people are bending the factory mounts. There is a difference between bashing a lower into a rock and deforming a raised upper from stress.

Another question. When and where does all of this geometry correction begin to matter? Is it on the street? Where and when do shocks show their stuff? If shocks and sway bars are a such a bandaid, why outboard and move mounts in order to fit better shocks. Should we be putting more emphasis on correcting geometry before shocks?

You can not want this thread to "devolve", but that doesn't mean you get to ignore pertinent questions about what does what and issues of context.
 
We cannot ONLY raise the uppers, Or ONLY redrill the lowers. Both operations MUST be done together or you end up with unsatisfactory results.

Nth degree brackets were not popular because they kept breaking and they were not friendly to use with lifts lowers than 4.5" due to clearance.

A 2" lift spring requires 2" rear bumpstop extension due to the coil bind height which is 5.5", also the same as most springs upto 4". This means there is no loss of uptravel by adding geometry correction brackets such as jeepwest weld on brackets. They require a 2" bumpstop extension without a body lift material is 1/4" steel with integrated bracing. If they rip off its because you can't weld.

The normal 2.5" lift rear shock @14" collapsed length requires 2" extension in factory mounts. If you add a tummy tucker, rotate the pinion then put shock shifters in the mix, you can end up needing over 3" of bumpstop extension.
Goto a 3.5-4.5" lift, 15-15.75" the bumpstop grows to 3.75" or more, regardless of what comes in the kit, they do not match.

The addition of geometry correction takes away suspension binding in a 12 travel range using outboard shock towers set up on a 2" bumpstop extension and has virtually zero rear steer from a 4" or less lift height.

20200418_215046.jpg
 
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David Kishpaugh said:
We cannot ONLY raise the uppers, Or ONLY redrill the lowers. Both operations MUST be done together or you end up with unsatisfactory results.

Nth degree brackets were not popular because they kept breaking and they were not friendly to use with lifts lowers than 4.5" due to clearance.

A 2" lift spring requires 2" rear bumpstop extension due to the coil bind height which is 5.5", also the same as most springs upto 4". This means there is no loss of uptravel by adding geometry correction brackets such as jeepwest weld on brackets. They require a 2" bumpstop extension without a body lift material is 1/4" steel with integrated bracing. If they rip off its because you can't weld.

The normal 2.5" lift rear shock @14" collapsed length requires 2" extension in factory mounts. If you add a tummy tucker, rotate the pinion then put shock shifters in the mix, you can end up needing over 3" of bumpstop extension.
Goto a 3.5-4.5" lift, 15-15.75" the bumpstop grows to 3.75" or more, regardless of what comes in the kit, they do not match.

The addition of geometry correction takes away suspension binding in a 12 travel range using outboard shock towers set up on a 2" bumpstop extension and has virtually zero rear steer from a 4" or less lift height.

View attachment 177447
Click to expand...

If you're going through all this trouble of moving mounts and retaining the track bar, why not do a rear 3 link plus track bar?
 
jjvw said:
Another question. When and where does all of this geometry correction begin to matter? Is it on the street? Where and when do shocks show their stuff? If shocks and sway bars are a such a bandaid, why outboard and move mounts in order to fit better shocks. Should we be putting more emphasis on correcting geometry before shocks?
Click to expand...

The need for geometry correction begins as soon as we put a 2" puck on top of a stock spring.

Outboards realistically do not add much stability. Yes, you can tell they are there but they don't magically cause the front tires to stay on the ground, add traction and control or make the rig predictable, geometry correction does.

I believe this thread was all about finding nth geometry correction.
Rear geometry correction is the single most dramatic change that can be done to a short arm suspension system from as little as 2" of lift. Adding outboad shocks and a 17" extened rear coil length allows us to use a 12" travel shock, the range of travel only a long arm could previously handle without binding but still have poor geometry.
 
David Kishpaugh said:
The need for geometry correction begins as soon as we put a 2" puck on top of a stock spring.

Outboards realistically do not add much stability. Yes, you can tell they are there but they don't magically cause the front tires to stay on the ground, add traction and control or make the rig predictable, geometry correction does.

...
Click to expand...

Which goes back to my question about when this all starts to matter. A 2" lift typically gets one to a 32" tire. Is this person going to be pushing the rig to the point where poor geometry is going to impede their progress?
 
jjvw said:
Which goes back to my question about when this all starts to matter. A 2" lift typically gets one to a 32" tire. Is this person going to be pushing the rig to the point where poor geometry is going to impede their progress?
Click to expand...

Poor geometry is poor geometry whether or not the person is going to push the rig.

Just to give perspective, here are two jeeps Dave setup. One jeep (red one) has the Jeep West geometry correction, the white one does not. Otherwise they are setup very much the same - they both have 4" short arm lift, 12" travel rear outboard shocks, 11.15" travel front shocks. Both jeeps are equipped with torsen rear LSD differentials.


https://www.facebook.com/video.php?v=1159203234212032



https://www.facebook.com/video.php?v=1159205487545140
 
jjvw said:
If you're going through all this trouble of moving mounts and retaining the track bar, why not do a rear 3 link plus track bar?
Click to expand...

three link rears do not have the stability and there is a good amount of rear steer with the antisquat adjusted to a point the front end doesnt bob. we have to rely on a heavy sway bar.

here are two examples I built under the tj. there are 8 of mid arm 3 links running around, the short arm 3 link jeep was turned into an LJ project a couple years but worked flawlessly. the belly pan is a rockmen, these were done close to 10 years ago. the short arm three link geometry is Identical to the geometry correction brackets I currently build.

threelinkmidarm.jpg


threelinkshortarm.jpg
 
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