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Figuring out suspension for coilovers and long arms

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4.3K views 17 replies 5 participants last post by  Tweak  
#1 · (Edited)
Hey so I have a JKU and I’m aiming to run 40’s and at some point in the future I will be getting one tons from Fusion to run the 40’s but one thing I’m trying to get sorted out is the suspension side of things. The cars gonna be a daily driver and I will be using it 75% in the city and the other 25% will be off-roading (Eastern Jeep safari, Rubicon trail, Moab).

Im waiting to get the axles to install the lift but I currently have a 2.0 king coilover kit that I got from Accutune Offroad and my thought process is that a 3 link long arm front and a 3 link long arm rear would let me get the most amount of Flex out of the coilovers so I’m considering on going with the X2 kit from Rock Krawler. As for driveshafts I was thinking Adams. My goal is to be able to get around 38-42 inches of articulation in case I ever go to a car event and want to flex my tire over another tire.

With the following parts I just mentioned would there be any issues I might run into or are there maybe better ways to get flex? Would the 3 link front and rear be decent ride quality for a daily driver?


I’ll link below the items I’m talking about in this post.

King Coilover 2.0 kit

Rock Krawler 3 link kit

Adams Driveshaft kit
 
#2 ·
I will let others speak to this. But coilovers are not always the best way to get flex. Great for ride quality and going fast over open terrain.
 
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#3 ·
You sound like a perfect candidate for a Jeep West custom 3 link front and geo correction rear... But he's in Oregon and it looks like you might be in Florida. That's about as not going to work as anything.

He's got a lot of photos of his work on his FB page. Jeep West In fact, yesterday he posted a 3 link JK front with geo correction rear and photos...

As for the long arm builders kits, I like the Clayton setup. And you could work with them to determine how your coilover setup would work with their kit.
 
#4 ·
Based on your axle thread it sounds like you will have a nice Jeep but overbuilt for the trails you are listing. That's no problem and it sounds like it will be cool cruising the streets and trails. Nothing wrong with the parts you are selecting but you aren't getting more flex than a traditional "mid-arm" JK suspension lift. It sounds like the coilovers are fairly nice without intrusion into the engine bay or rear tub but a properly placed 12" travel shock will get you the same flex. Because of the 40s or 42st that you are considering your realistic up travel will be compromised unless you do some major hacking so you may not get the advertised 5" of up travel; but, you'll have no problem with the droop part. If you only get 3" of up travel you have turned that 12" coilover into 10" of shock/coil travel. That will equate to more travel at the wheel since the mounts are inboard but that also applies to traditional shock and spring suspension too. 3-link, triangulated 4-link, standard arm, typical long arm, radius arm, they will all give you the same amount of flex on that 12" coilover kit. The suspension will feel different and the arc that the wheel travels will vary based on suspension but the links can't make a 12" coilover suspension flex more than the length of the coils. It also looks like the coilover kit gives you 5" of lift which isn't bad but isn't always needed for 40s but maybe for 42s. There are plenty of people on lower lift heights and 40s.

Most kit oriented 3-links make compromises in suspension geometry for packaging. That may not be terrible and it can be tuned out some with the proper shocks and springs. I'm not a suspension expert so I can't give advice on tuning. Overall any of the suspension link versions that still require a track bar start seeing issues after 12"+ of actual shock/spring travel. The TB pull the suspension to one side of the frame or other a lot more as the suspension articulates past ride height. It is common for high articulating track bar suspension to offset the axle from center at ride height to allow for clearance during the full range of suspension travel. It is possible for the axles to shift over 5" side-to-side because of the way the TB operates. Since you are staying with a safe amount of travel most of these issues are easy to overcome. Since you will be doing 1 tons you will have a raised TB in front which is good; I would make sure your rear axle track bar bracket offers 6" above factory location. Teraflex makes an excellent weld on bracket for bigger axles. Many of the standard brackets only offer 4-5" above stock. This is the best way to get that rear TB close to level.

If I was you, I wouldn't go with a kit coilover kit because you most likely won't be maximizing the travel of the kit unless you ask the manufacturer what flares, tires, and wheel offset they were testing with? That kit may have been designed around 37s which would use the full 12" while 40s or 42s may only use 10" based on the location of the upper mounts. If you have time and the space, I would order the axles, wheels, tires, fenders, then start figuring out desirable ride height and articulation. Once you get that figured out maybe it will be more clear what suspension type will work with the intended travel. My personal opinion would be that I would not want to use stock location low hanging axle mounts on $20,000 axles and tires. If I was going that far I wouldn't want to use a suspension that is designed and limited to the factory axle bracket locations. Just 1 point; a rear dana 44 with 37s and altered lower shock mounts offered by Metalcloak, Synergy and others will have better overall ground clearance than 60s or 14 bolt with that bolt on coil over kit. I don't like how low those rear coilovers hang but with 40s or 42s that may not be important to you based on the trails you listed.

It's your Jeep and have fun! Write down your ultimate goals and try to stick with them. Trying to buy all the parts at once sounds nice but more than likely there will be some parts that weren't designed for your tire size and goals and you may regret buying everything at once. You are in the territory where suspension kits, 1-tons, and 40s-42s don't mix well on the trail without proper planning. You are honestly in the custom build territory to maximize the benefits of 40s and 1-tons. Don't buy driveshafts until everything else is built and you can get actual measurements. You may be shifting axles forward and back to get them to sit properly in the wheel wells.
 
#12 ·
So as for fenders I currently have some Genright fenders and i have some Evo front inner fenders so I’d say I have that part of clearance done but I haven’t bought long arms yet cause I know that’s a trickier thing to get right then it is to go up (lift the car up).

I want to run king coilovers for sure, I was really just struggling with where to get the kit from It was either Evo or if not Rebel off-road and then I found out about Accutune and besides being good price it asks for your build specs to custom tune the coilovers to your build and the way the kits gonna be used so to me it was the more custom kit rather then ordering a kit and bump stops and having nothing custom about it.

As for driveshafts definitely leaving them for last. I previously bought a Teraflex alpine CT4 Long arm kit (4 link front and rear) but I talked to a Jeep mechanic I know and was told that rock krawler is a better brand as there long arms are thicker and a overall tougher kit. I know that rock krawler also sells another kit with a 4 link front and a 3 link rear which i, do you think this is a better kit in terms of daily driving comfort but still getting good articulation from the coilovers?

I sorta just assumed a 3 link front and 3 link rear would give me the best flex I can get but I mean if the daily driving comforts gonna be horrible in exchange then not sure if it’s a good idea. I want to get as much flex out of the coilovers while still having comfortable driving quality. I understand I am aiming for 40s so high flex isn’t as easy to obtain as if I went 37s and all. I have yet to get the axles as they’re pretty expensive but when the time does come around then I can surely order a custom trackbar mount to work better with the 3 link front but like I said I still want to get your opinion on the last question.

(If I see the build well equipped to run a trail then I’ll hit it. I’m not gonna stay close minded to easy and intermediate trails if it looks capable for a harder trail then I’d certainly be open to hitting that trail)

Thank you for all the input!

4 Link front/ 3 Link rear kit
 
#8 ·
My perspective on the coilovers is that a custom setup done well will outperform most other builds. But a generic off the shelf setup isn't anything special. Without having them on the CTI trailer to see the real numbers, the Metalcloak 15" six paks would out flex a typical 12" coilover "kit".
 
#15 ·
Would you agree that the 3 link front and 3 link rear would get me the most flex out the coilovers and still be decent driving or would the 4 link front and 3 link rear (the kit I mentioned in post #12 on this thread) be better on road handling and not sacrifice too much flex and still manage some 38-40in flex?

Thanks for the input!