Help with CJ7 on coil springs

Desert rat

Desert rat

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Joined
Sep 26, 2020
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El Paso TX
I need advice from you wrangler guys. I have a 81 cj7 that I've had for over 20 years lots of mods done to it 350 chevy tbi, 700r trans, dana 44s front /rear, so on and so on. I always loved the ride of a tj wrangler so i decided to copy the suspension of a 2000 tj . I built a three link setup and used stock tj coils for that nice soft ride. Problem is its too soft. With skyjacker shocks 7000s . You can push the front or rear up and down with your hand ,it is like a car. Have you guys ever tried this on your wrangler with out the shocks on? Mine is like a pogo stick with out the shocks on . So i need to go a stiffer shock but which one I want that smoth stock tj ride, I not hard core rock 4wheeler , so I don't want it too stiff. . Some of you guys talked about 5000 ranchos would this be the way to go ? anyone know the rating of this shock compared to what the factory put on a stock tj? Thanks
 
I have bounced my TJ with the shocks off and yes, what you're describing is normal.

I've never had skyjacker shocks but I have rancho rs5000x and I like them. Don't know how they compare to stock because mine had rs5000 (without the x) when i bought it. Don't get the 5000, you want the 5000x.
 
That's a tough deal.. because so much has been changed on the chassis ...first I'd second guess the spring rates you have .

Bilsteins may be worth looking into also.
 
Thanks guys I'm glad to hear that your tj has the pogo stick movement with out the shocks on. This is new to me because with the old leaf springs I had I could not move it with or with out the shocks on. I just ordered a set of rancho 5000x shocks ,they will be middle of next week so I'll try them and if there not stiff enought I'll have to go with a higher presser then the 150psi that the 5000x has, so we will see.
my cj.jpg
 
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How much did the springs compress when you put it on all 4 wheels? Measure the front and rear springs from top of the coil to the bottom of the coil. Compare that to the known spring height of a factory tj(there is a thread somewhere on the forum with that info) if the springs are shorter that a second tj at ride height that will tell you the spring rate is to light. When you add shocks if you want a stiffer ride use bilstien 5100's
 
Front compressed from 17" to 12" rear from 12" to between 9" or 8" but I think the are ok ,the jeep sets about a 1' higher than it did with the old leaf springs and I have 12" of total travel in front and 8" in the rear where before I had only maybe 6".
 
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Man that is bad a$$ for sure. If I remember correctly one of the 4x4 magrags I am think Peterson Four wheel and off-road did a CJ coil spring swap back in 94-96 it was before the TJ came out. You might be able to Google it.
 
My friends and I have converted a few cjs to coils. We have used 150 lb springs in the front, and 150 to 200 in the rear.

Your spring compression sounds about right.

Most of the guys I run with use a bilstein 7100 shock valved 255/70. The 7100 has a linear piston instead of the digressive that the 5100 series has. They ride much smoother than the 5100 series.

You can get the 7100s in 8,10,12 inch travel. Try to pick a shock length that allows for a 50/50 travel split( 10 inch travel, 5 up 5 down.


Are you using tj style mounts? Might be able to find a Fox that meets your requirements.
 
The shocks that i choose have 12" travel ,6" up, 6" down for the front and 10" travel in the back 5" up and 5". The shock mounts are custom upper and lower eyes. Axles are 44s front is from a Wagoneer that I had to cut down the driver side, rear is kind of cool , it's a dana 44 that comes stock in a Isuzu Rodeo. These come in three widths so you can have a wide track dana 44 like came in a 86 cj7 or in my case I wanted it to be about the width of a tj to match the front which gave me room for out side frame front springs. Plus they come stock with 4:11 or 4:30 gears. I chose the 4:30s and matched the front , and they come with disk brakes, I picked up the rear end for 115$ at the local pick a part, what a deal! Here are pics of the front and rear mounts I fabbed up.
cj front coils.jpg
cj rear coils.jpg
up.
 
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Desert rat said:
The shocks that i choose have 12" travel ,6" up, 6" down for the front and 10" travel in the back 5" up and 5". The shock mounts are custom upper and lower eyes. Axles are 44s front is from a Wagoneer that I had to cut down the driver side, rear is kind of cool , it's a dana 44 that comes stock in a Isuzu Rodeo. These come in three widths so you can have a wide track dana 44 like came in a 86 cj7 or in my case I wanted it to be about the width of a tj to match the front which gave me room for out side frame front springs. Plus they come stock with 4:11 or 4:30 gears. I chose the 4:30s and matched the front , and they come with disk brakes, I picked up the rear end for 115$ at the local pick a part, what a deal! Here are pics of the front and rear mounts I fabbed up.View attachment 192394View attachment 192395 up.
Click to expand...

You'll never make those shocks work with those springs.
 
Are you referring to the skyjacker shocks, which I've already stated don't work or the rancho 5000x which i've ordered to try next?
 
Desert rat said:
Are you referring to the skyjacker shocks, which I've already stated don't work or the rancho 5000x which i've ordered to try next?
Click to expand...
Stock TJ springs do not have enough spring travel to support a 12" travel shock. You'll need something like Currie in the 4" lift range.
 
You could measure your travel by jacking up the jeep by the bumper until the springs just unseat. That would be down travel
Pull the springs and let it down until it hits your bumpstops, without the bumpstop rubber in. The rubber will compress basically all the way.

Thar will be your approximate total travel. When you articulate the axle around, you will probably see a bit more travel.

A longer shock with the travel split about in half is ok as long as you dont bottom the shock out. Do you use limit straps or use the shocks to limit down travel? We have been using straps to keep the springs from unseating too much.
 
Thanks for you input. First when I built the suspension one of the factors I wanted was more axle travel as I only had 2.5" to 3". before I hit my bump stops. I still don't know how much the springs will fully compress but in the front I set my bump stops 5" from the bottom spring mount so as not to bottom out the shock, on the other hand downward axle movement is greater than 6" so a limiting strap should be used to limit drop a 5" to 6" so the shock does not top out. I have a tab that clamps the bottom of the spring to the bottom spring bracket which will keep the spring seated to the mount. The top of the spring can drop down from the upper mount but not so much as to come out from the upper bracket due to the length of the bump stop. So with a12" shock mounted midway, at ride height (6" from toping out and 6" from bottoming out) I have my 11"to 12" of travel. The rear is similar and will have 10" of total travel. both axles have been articulated through their movement cycle to check for clearance. The jeep sets about 1" taller than it did before which over all is about a 3" lift from a stock cj7, but with much greater axle travel. I see no problem with the springs, the issue is the shocks that I tried at first. Since the goal was a smooth ride I wasn't going to start off with a super stiff shock the would have defeated the whole point of this conversion, so I started off soft and will increase shock stiffness until ride objective is reached. Have I missed something?
 
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