What coils to use on a 40 (1 Viewer)

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West MI near GVSU
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www.mcdesignsoffroad.com
I've decided to build a coil link settup on my 40. A friend gave me some stock XJ front coils that I thought might work well for the rear. I was thinking of using 80 coils in the front. On both ends I'll probably mount the coils to my lower link near the axle to allow more travel based on the idea of a lever.

I currently have a 350, but would like to go with a 4bt eventually. I will run a 37-38" tire and am building 58" WMS axles for a little more stability and added forced articulation. I'll probably add some quick disconnect swaybars for road and utility use.

My goal is stable flex for all around use and added wheelbase; probably 96-100".

Suggestions?
 
I say use what you have......but
Coils are a much better ride .....
If yah go with coils... def...give slee or cruiser outfitters a call...
I did and like the results I got....
Although, not a 40 my 60 is running J's on the front and slee's 4" heavies on the rear.
She sits level empty or loaded and ride is nice n smooth......
 
Thanks. That's good info. How much vertical travel do you think each spring is capable of making? I will be mounting them on the lower control arm so the axle can a little more travel beyond the spring.

Enough. Not as much as the Wrangler springs but what good is crazy articulation if you're not stable

Explorer springs

DSC06503.jpg


Wrangler springs

PYS2009258.jpg



Both sets are captured at both ends. I ran loose springs. That was no good.
 
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Enough. Not as much as the Wrangler springs but what good is crazy articulation if you're not stable

Explorer springs

DSC06503.jpg


Wrangler springs

PYS2009258.jpg



Both sets are captured at both ends. I ran loose springs. That was no good.

So what you are saying is the stock wrangle springs are to soft for a full FJ55. The reason i am asking is I have a set and was thinking that they might work for DD and have good flex for the trail.
 
I have heard that wrangler fronts work alright in the rear, no direct experience though.

The 2F is a heavy pig, if you are running a different engine thats a game changer for the front, 40's aren't that heavy.

If you want to run the coils on the link you will need to run a bushing or a wobble stopper at the frame end to keep the link from rotating, unless you run a bent link with the coil mount below the link centerline.
 
coil mount

My link arms are going to rotate with the axle. The springs would flex just like on an old Ford radius arm settup. All of the hinging and rotation will be taken up at the frame mounts.

I also won't build coil mounts that allow the coils to float. It doesn't seem safe and allows too many extra wear and fatigue points as well as the clatter of the hanging springs while unloading and reloading. I have a stubborn Jeep friend who insists its the best way, but his junk is always broken too.

I would like to find an old frame to build the settup onto and then transfer it over to my truck. Currently I'm going to see what 60 rear packs and SOA handle like. Both of my kids want to build 40s.
 
Back at it

I have been going back and forth with doing the 60 rear packs for a SOA and I think I will start building my link suspension. I now have a lot more metal to play with at work and commercial welders. I'll keep the leaf stuff for one of my kid's 40s.

The idea right now is to use a 42" pivot arm length between the axle center and the frame mount. I'll push the front axle 3" forward and rear 1.5" more than the 3.5" spring flip for a total 98" WB. Both ends will use a two-link settup that articulates like crazy and will not allow for any axle wrap. It will basically be like an articulating swingarm. I'll add pictures as things progress.

The 40 is just sitting idle right now. Is there any better time to play?
 
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I too am going to use coil springs up front, I don't mean to high-jack but a few questions; for the Explorer cols did you have to cut them down or did you just use them as they are? Also what would be another good spring for the front, I have pretty much the same set up as 69LC does except I will be using 39.5" Iroks.

69LC does a lot of great work, I am lucky that he lives nearby. Looking forward to what he does and to all comments on this thread.
 
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get your front and rear weights and other measurments like suspension travel, ride height etc. and call up someone who can give you some good advice like Tony at TK1 or Jim at Poly performance, etc. and get you some Eibachs or something similar that will have the correct spring rate for what you want to do.......there are several folks making the axle and frame mounting plates for smaller diameter springs now
 

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