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Help: 6.4L JK with Icon Coilover Spring Rate

Old 02-18-2018, 09:46 AM
  #11  
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For some reason Icon uses a heavier coil on top.
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Old 02-18-2018, 06:17 PM
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Originally Posted by TheDirtman View Post
One more thing to look at is your stop nuts. Where are they set at? You photo to me looks like the bottom coil is taking all the weight of the jeep. Do you have any more photos of the shock showing the stop nuts?
The coil is not hitting the stop nuts, it is a little hard to tell from this picture but it is up higher than the lower spring. I am also only running 35" tires. The goal here is to get the full use out of this suspension and not damage anything.



I did a little more research last night and have determined the following:

By spec the stock Rubicon should be 9.375" based on the measurement lcoations below:



I went to the local dealership yesterday and took some measurements at the same location on some stock vehicles:

Vehicle #1: 4 Door Rubicon: 10.0"
Vehicle #2: 4 Door JK: 9.75"
Vehicle #3: 4 Door JK: 9.75"

I then measured my Jeep as it sits and it is 10.75". So my Jeep with the Hemi, winch and Icon suspension is only sitting 0.75" higher than a stock Rubi. That is definitely not the 1.75-4" that the Icon advertises.

I took a look on Icons site and they say that you cannot adjust the stop nuts more than 3.25"

"DO NOT PRELOAD THE COIL BEYOND 3.25” OF EXPOSED THREADS BETWEEN THE BOTTOM OF THE TOP CAP AND THE COIL ADJUSTER NUT. ADJUSTING PRELOAD BEYOND THIS SETTING WILL CAUSE THE COIL TO BIND AND DAMAGE WILL OCCUR TO COILOVER AND/OR VEHICLE."

My coil adjuster nut is near 3.25" right now, with that said I believe that I definitely need to get higher spring rates for the two coils

Effective Spring rate = ( Rate 1 X Rate 2) / (Rate 1+ Rate 2)

Stock Icon Effective Spring Rate = (350 X 200) / (350 + 200) = 127.27

I then measured from the resting position to full droop and found that that travel distance is 7.27"

By calculation only and this could be a little off since there is a pre-load on the springs, the force is (7.27" X 127.27) = 925.25 lbf per side.

For example if I want to get a 3" lift out of this system, and there are infinite combinations here, then I would need something like a (375/425) combination. Am I way out here in left field?

Last edited by Covalent; 02-18-2018 at 06:54 PM.
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Old 02-18-2018, 07:02 PM
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Originally Posted by Ryan0260 View Post
So how bad is the front sagging? I run the stage 2 ICON coilovers, but they are the 4.5" -6". There is zero sag and plenty of adjustment if that was even an issue. Their coils are made by Eibach, so finding a different rate should not be a huge deal. Call Scott at ICON and get his input.

My kit came with huge bump stop extensions which severely limited travel, so I ditched them when I swapped in my PR44. I am using tje Dynatrac bump stops and all is good now.

What size tires are you running? I thing the kit you have on your JK is really suited for 35" tires and under.
I am running 35" tires and with this suspension I am only getting 0.75" of lift with the nuts turned down to almost the max amount of 3.25" that Icon recommends. I believe I need higher rate coils for sure.

How high did your 4.5-6" Icon raise your rig?
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Old 02-19-2018, 07:28 AM
  #14  
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I would wait to figure what you need until you can set the shocks at zero preload with them charged at 150 psi and see how they sit on the jeep because preload and the pressure will have an affect on the coil rate you need. Right now the rates you are suggesting seem high but you also have a 10" shock which would have to take a larger rate to allow for up travel.
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Old 02-19-2018, 10:11 AM
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Originally Posted by Covalent View Post
I am running 35" tires and with this suspension I am only getting 0.75" of lift with the nuts turned down to almost the max amount of 3.25" that Icon recommends. I believe I need higher rate coils for sure.

How high did your 4.5-6" Icon raise your rig?
I have mine set fairly low probably in the 3.5" to 4" range. ICON definitely estimates on the high end of actual lift. Many manufacturers average the amount of lift between the front and rear and figure the average in their advertised amount of lift. I am running 37's, and the max adjustment on mine is to be able to clear 40's.
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