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Hello. I have been thinking about whether I need 650lb or 700lb front coil springs. I added 360ish lbs to the front of my fj in a front bumper and winch (a very heavy road armor front bumper). Some people say to go 700lb while some say 650lb. Is the 700lb going to be a stiff ride?

Also. If I change my suspension from stock to something like the toytec boss or icon stage 1 do I need to get better upper control arms (coming from stock upper control arms). Is it a must? What if I keep my stock upper control arms?

Thanks so much.
 

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Before continuing, I will say that I am relatively new to the FJ scene (only owned it 11 months so far) but no one else has replied as of me typing this so I'll chime in.. I don't know much about the coils so I guess the next poster can help with that. However with a lift, new UCAs seem to be always recommended but not always used. What I mean is that many run the stock control arms with lifted trucks and report no problems while others claim that doing so will turn your truck into a rolling deathtrap and will cause world war 3 (over exaggeration, but I've come across people with some pretty strong feelings about it). I can't speak from experience because my FJ is still running completely stock suspension. When I upgrade to either Bilstein 5100 adjustables or ProComp 3", I plan to also install aftermarket UCAs because from my research, it seems that only that will ensure being able to get the FJ's alignment back to spec.

In short: Idk about coils, but I recommend getting aftermarket UCAs if you lift your FJ.
 

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Discussion Starter #3
Thanks ams for your reply. I have decided to get aftermarket upper control arms based on your help and some other research.
 

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With all the added weight in the front IMO the 700lbs will be just fine.
 

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I ran 5,100's for about 80,000 "Cowboy" miles with the stock UCA's. Mikey is right about the springs. I did go aftermarket UCA's when I got extended travel shocks up front (which I have lifted 2 3/4". If I was asked to give an honest recommendation on the two shocks you mentioned. Icon Stage one hands down. I have no complaints with the 5,100's. The Icons performance is "Next Level"
 

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Yep, go with 700s. I had 650s and later upgraded to 700s, glad I did. Don't really notice it being any stiffer, but it's definitely more stable.
 

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Hey there. So I have the Icon 650 pound for my fj with the icon upper control arms. Is there a link that anyone has for the 700 pound springs? I'm wanting to upgrade but can't seem to find them.
Thank!
 

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What is the stock Spring Rate (k) Versus the aftermarket k value (just saying a 700 lb spring means nothing!). If you know the stock rate and the change in vehicle height before and after your mods, you will be able to determine (calculate) your ideal stance height without guess work! another way to look at it is:
You added 400 lb of mass and the front end sunk 2 inches, that is a spring rate (k) of 100lb/inch for each spring. if the factory spring rate 500 lb/inch then a k-final value of 600 lb/inch is required!

GL
 

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Older OME struts could only use OME springs. What OME struts do you have? Yellow is not an acceptable answer.:)
I will have to try and find out the other owner covered a lot of stuff with undercoating so my OME shocks are half black.
 

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I am getting front end sag with steel bumper and skids how do I know what length of spring I need? It had OME shocks on it when I purchased FJ. These Summit Racing look good if they are right length.
You'll probably want 14" long.
 

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You'll probably want 14" long.
Go with 700 lb? I am not sure the age of my shocks or how good they are I wonder if I should get shocks too?
 

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At one time older OME could be fitted 3 different spring weights. When I used them with ARB bumper, winch, and extra battery I used the springs labeled heavy springs. First off before you can do anything you have to find out what you are working with. That is not entirely true, I mis spoke. To do it right you need to figure out what you got before moving forward.
 
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