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Discussion Starter #1
Just modeled my new suspension on the V3.0 4 link calculator and here is what I came up with.


Anti-Squat 134 %
Roll Center Height 21 in
Roll Axis Angle 9 degrees (Roll Oversteer)
Instant Center X-Axis 84 in
Instant Center Z-Axis 28 in



This in a 107" wheelbase rig..
Any input??.. I have tried to get the AS numbers lower, but the only way is to either lower the rear mounts for the upper links (can't do) or Raise the front frame side mounts for the upper links (dont have room either, its a unibody vehicle)

Any input as to how anyone will think this will handle??
 

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When I read in a post ahwile back it seemed that alot of people were syaing over 150as was good for trial rigs for sure.You might post what terrian you are mainly on.They also posted that one of the old comp buggys was at almost 300.I am thinking by what everyone was telling me that you want some antisquat to force the traction to the rock's but don't want to much so the axle crawles under you.You might post a pic of everything like I did when I got schooled on this thing a few days ago.Here is mine.

 

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UUUUUUUUMMMMMMMMMM

Wow, oh my...

Might want to drop the AS to 80% or less.
Or else you will get wheel hop when climbing

Also a little roll understeer is ok and MUCH better than roll over steer.

You also need to look at what your suspension #'s are within a few inches of ride height (4in of droop and compression??????)
 

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Discussion Starter #4 (Edited)
I have been messing with the mounts, and, just dont have much room to work with a Unibody, as I cannot do a body lift to get the frame side mounts up higher.

I have 5" of up travel (using custom mounts and 14" travel shocks..) so I have plenty of droop..
I dont think down travel is the issue

The biggest issue is that i cannot get more than 4" of vertical seperation of the frameside links, because of clearance with the floorpan issues.


I just dont have much room for adjustment for the rear link either, but I guess I will play with it a bit..

thanks
After doing some tweeking, here is what I can get away with, anything else, and I run into serious issues.

4 Geometry Summary:
Anti-Squat 107 %
Roll Center Height 23 in
Roll Axis Angle 9 degrees (Roll Oversteer)
Instant Center X-Axis 143 in
Instant Center Z-Axis 38 in
 

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You need to keep adjusting.

What are the Analysis #'s at 4" of compression and 4" of droop.

Static info is great but not the whole picture. If you get 199% AS at 1in of droop (or even 4") you are going to have problems.

You really should try to achieve roll under steer.

Have you tried adjusting how much they converge from the top view?
 

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Discussion Starter #6
K, I played around with where the mounts will go and here is the other option to the above that I have come up with.

Anti-Squat 174 %
Roll Center Height 23 in
Roll Axis Angle -3 degrees (Roll Understeer)
Instant Center X-Axis 57 in
Instant Center Z-Axis 25 in
 

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You need to quit posting the same set of numbers over again. I think by now you know what that set should look like. Your main issues now are going to be pinion angle and anti-squat during suspension movement, which is why you need to look at the suspension at other places besides static ride height.
 

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Ok OK read my fortune.....what do my numbers look like????
Wheelbase 114.0 in Upper Links x y z Anti-Squat 120 %
Tire Diameter 42.00 in Frame End 40.50 22.25 26.25 in Roll Center Height 25 in
Tire Rolling Radius 21.00 in Axle End 0.00 16.00 27.00 in Roll Axis Angle -2 degrees (Roll Understeer)
Vehicle CG Height 30.00 in Lower Links x y z Instant Center X-Axis 75 in
Vehicle Mass 3,000 lb Frame End 44.00 4.00 22.50 in Instant Center Z-Axis 26 in
Front Unsprung Mass 800 lb Axle End 0.00 20.00 18.00 in
Rear Unsprung Mass 700 lb
 

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Well, looks like you've got about 120% antiquat, some roll understeer. I'd guess about -2 degrees.

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What exactly are you trying to accomplish?
 

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Discussion Starter #10
Um Yeah, just trying to get a little advise, keep in mind this is a daily driver trail/DD vehicle, around 5,200lbs, Jeep Grand cherokee.

here are the full numbers, sorry if it is redundant

Bump Geometry
Geometry Summary:
Anti-Squat 167.341 %
Roll Axis Slope -0.3170 in/in (Roll Understeer)
Roll Center Height 35.599 in
Roll Axis Angle -17.586 degrees (Roll Understeer)
Instant Center X-Axis 44.702 in
Instant Center Z-Axis 20.252 in


Droop Geometry
Geometry Summary:
Anti-Squat 204.376 %
Roll Axis Slope 0.1255 in/in (Roll Oversteer)
Roll Center Height 19.750 in
Roll Axis Angle 7.152 degrees (Roll Oversteer)
Instant Center X-Axis 61.989 in
Instant Center Z-Axis 33.591 in
 

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I'd reconsider something there...your droop anti-squat seems a bit high. I'd be worried that the axle is gonna want to run right under your rig if that's the case.

Like was said before, by TRD:
"If you get 199% AS at 1in of droop (or even 4") you are going to have problems."

You can use the calculator to get a rough idea of what your link placement is going to accomplish, but unless you know EXACTLY the behavior and geometry that you want, it would be beneficial for you to make several mounting points for your links. Many guys will do this to allow for easy changes after fabrication and testing, without having to grind off link mounts etc.

Just curious, what kind of axle do you have in mind here?
 

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Discussion Starter #12
I already have the axles under the rig using the stock type suspension.

Axles are a Low Pinion Dana 44 with "super 44" kit with detroit locker

Front axle is a High Pinion D44 with Arb, warn hubs, ctms, warn axles..

I converted to a Radius style front arm assembly about a year ago, and long lower rear arms, but still have the short uppers and a trackbar in the rear, and want to convert that to either 4 link or 3 link rear.

Trying to find a happy medium between stable off-road and on road DD capabilities.

It currently also has a Currie Anti-rock in the rear and a Swaylok in the front
 

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TheRipper said:
When I read in a post ahwile back it seemed that alot of people were syaing over 150as was good for trial rigs for sure.You might post what terrian you are mainly on.They also posted that one of the old comp buggys was at almost 300.I am thinking by what everyone was telling me that you want some antisquat to force the traction to the rock's but don't want to much so the axle crawles under you.You might post a pic of everything like I did when I got schooled on this thing a few days ago.Here is mine.

:laughing: :laughing: :laughing: :laughing:

I want some of what you got :smokin:
 
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