JKS JSPEC suspension kit

Let me get this straight, @Fargo, you’re getting 2.5” lift in the rear and @Farmergreg, you’re getting 2.75”? (Cool springs only)

Forget all those measurements from the bump stops, et al, I’m just referring to the traditional measurement. I’m thinking of moving to these coils. Thanks for confirming it negating.
 
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JMT said:
Let me get this straight, @Fargo, you’re getting 2.5” lift in the rear and @Farmergreg, you’re getting 2.75”? (Cool springs only)

Forget all those measurements from the bump stops, et al, I’m just referring to the traditional measurement. I’m thinking of moving to these coils. Thanks for confirming it negating.
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Yeah, you buy them and let me know you're lift height and travel. That will help me decide between those and Savvy 3" springs...
 
Mike_H said:
Yeah, you buy them and let me know you're lift height and travel. That will help me decide between those and Savvy 3" springs...
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I could have got those 3” savvy’s Nicksgeep was selling, but I think you’ll only get 2.25-2.5“. I thought you would be on 4” Currie and 35’s by now. You’d get closer to 3” w the JSPEC or maybe BDS (then you’d be in the big dick club too!)

Edit: what about OME 2934 in the front? 510mm and 160ft/lb, gives ~ 3.5” on a stock TJ. It would be close to 3” on your rig.
 
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JMT said:
I could have got those 3” savvy’s Nicksgeep was selling, but I think you’ll only get 2.25-2.5“. I thought you would be on 4” Currie and 35’s by now. You’d get closer to 3” w the JSPEC or maybe BDS (then you’d be in the big dick club too!)
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No, I just wanna stay where I am, really. I want longer shocks, and I think I'll need a longer spring to get the shocks I want. The 35 thing is just hanging around, but my jeep really does do almost everything I want it to, right now. Once in a while, I get stuck in mud...but other than that, its great.
 
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Mike_H said:
No, I just wanna stay where I am, really. I want longer shocks, and I think I'll need a longer spring to get the shocks I want. The 35 thing is just hanging around, but my jeep really does do almost everything I want it to, right now. Once in a while, I get stuck in mud...but other than that, its great.
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See the OME 2934.

yeah, I was tempted to go to 35’s, but I just don’t see trails that demand them. Everyone else is running 37’s, but it’s just not necessary, and it’s more fun running 33’s and doing the same stuff!
 
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JMT said:
Let me get this straight, @Fargo, you’re getting 2.5” lift in the rear and @Farmergreg, you’re getting 2.75”? (Cool springs only)

Forget all those measurements from the bump stops, et al, I’m just referring to the traditional measurement. I’m thinking of moving to these coils. Thanks for confirming it negating.
Click to expand...

I'd have to measure again, but I think I got a solid 3" in the rear. I know I have a 10mm (3/8") OME spacer in front to account for the weight of the winch. That brings my front up to a 3" lift. I have an LJ and the rear with hardtop and steel bumpers is very level with the front. So I think I am at 3" all around.

JKS really did a good job on these as far as I am concerned. Unless you are really heavy, you should get the full 3" of lift. I'll try to measure them again or see if I can find my previous measurements, to confirm this, but it might be awhile with Christmas this week.
 
JMT said:
Let me get this straight, @Fargo, you’re getting 2.5” lift in the rear and @Farmergreg, you’re getting 2.75”? (Cool springs only)

Forget all those measurements from the bump stops, et al, I’m just referring to the traditional measurement. I’m thinking of moving to these coils. Thanks for confirming it negating.
Click to expand...
Just add 1" coil spacers. With the spacers and the OME 933/942 combo I'm getting 3" of lift. I'm also running the JSPEC shocks. They seem to be riding about the same as the RS5000X shocks, but give me a better travel bias.(55/45).

Edit to add: @Thunderhead got the Currie 3" springs and netted 3" of lift.
 
bobthetj03 said:
Just add 1" coil spacers. With the spacers and the OME 933/942 combo I'm getting 3" of lift. I'm also running the JSPEC shocks. They seem to be riding about the same as the RS5000X shocks, but give me a better travel bias.(55/45).

Edit to add: @Thunderhead got the Currie 3" springs and netted 3" of lift.
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Thanks for that tidbit about Thunderhead.

Yeah, I'm running the OME 933/942 combo with a 1.5" spacer up front and the 10mm spacer in the rear. Up front I'm netting 3.25" and in the rear 3" (no spare). I might as well stay with this. I'm not unseating my front springs, so I guess it doesn't matter. It would just be an OCD waste of money.
 
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JMT said:
Thanks for that tidbit about Thunderhead.

Yeah, I'm running the OME 933/942 combo with a 1.5" spacer up front and the 10mm spacer in the rear. Up front I'm netting 3.25" and in the rear 3" (no spare). I might as well stay with this. I'm not unseating my front springs, so I guess it doesn't matter. It would just be an OCD waste of money.
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So your 933s only net you about 1.75"? Using a 1.5" spacer seams like a lot of spacer. With that much spacer I would be concerned that you are getting into full coil bind before you are compressing your bumpstops. It seems like switching to the heavier 934 would be a good match for your rear springs.

The JKS might also work since their soft rate is a little firmer than your front spring. But I think you would find yourself most often in the firm rate. Your weight ratio sounds very different than others. It sounds like you are very light in the rear and heavy in front. Because of that, you might be best to simply replace the front with the more firm OME.
 
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@JMT an inexact science measuring springs!
Overall length of spring as the TJ sits:
Rear 10 7/8 -11”
Front 14 7/8”

The original rubber spring “cushions” are in place. Springs have been on for 2 years but only about 6K miles.
 
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Fargo said:
So your 933s only net you about 1.75"? Using a 1.5" spacer seams like a lot of spacer. With that much spacer I would be concerned that you are getting into full coil bind before you are compressing your bumpstops. It seems like switching to the heavier 934 would be a good match for your rear springs.

The JKS might also work since their soft rate is a little firmer than your front spring. But I think you would find yourself most often in the firm rate. Your weight ratio sounds very different than others. It sounds like you are very light in the rear and heavy in front. Because of that, you might be best to simply replace the front with the more firm OME.
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Less actually. I just went and measured again. 1.5” from the OME and 1.5” from the spacer up front. What’s weird is the only sprung weight I've added to the Jeep up front is a 39lb Warn Rock Crawler Bumper, 60lb winch, Front upper and lower CA's, and the MML's, minus the stock bumper weight. 🤨
 
Mine is an LJ with the hardtop on, stock front bumper, aluminum winch plate and warn 8k cheap winch with dyneema rope
 
Farmergreg said:
Mine is an LJ with the hardtop on, stock front bumper, aluminum winch plate and warn 8k cheap winch with dyneema rope
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Ditto "Mine is an LJ with the hardtop on, stock front bumper," but I have a steel winch plate with a Warn 8000 winch and steel cable. Which is why I netted 14 1/2 and you got 14 7/8. Hard to believe the extra weight of a steel plate and steel cable would make that much difference. I wonder how much weight difference is in the winch itself. My rears should be pretty close to the same as yours. rear springs are hard to measure because they sit at an angle and the front of the coil compresses more than the rear.

JMT,
I suspect the JKS coils would give you slightly less lift than I have up front. My guess is that the JKS coils would give you about 14 3/8" (2 3/8" of lift). So you would still need a spacer up front to bring it up to the rear. I think the bigger unknown is the rear. You might need to put your spare tire back on to bring the rear down a little. The JKS is a firmer spring and its also taller than your OME. So I would expect that you would get 3 1/2 +" of lift in the rear if the OME 942s are giving you 3" already.

If your OK with a little more height and using a 3/4" spacer up front I think the JKS coils would work well for you. If you just want to get rid of the 1 1/2" spacer upfront, then the OME 934 might be a better option.
 
I'm going to recant what I said above. Thinking about your Jeep, I think you are so light in the back, that the JKS springs might raise the rear so much that you might still need a 1" or more spacer in front. If you install JKS springs you are increasing both the front and rear spring rate. So you could end up in a similar situation as you are know. As much as I love my JKS coils, I think you are better off to just get the OME 934 for the front of your Jeep.
 
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@JMT, measure from the bottom of the frame where the rear lower control arm mount is welded to the forward part of the frame to level ground. You can do the same at the front lower mount. Those measurements should be pretty consistent amongst our TJ's/LJ's.
 
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JMT said:
Less actually. I just went and measured again. 1.5” from the OME and 1.5” from the spacer up front. What’s weird is the only sprung weight I've added to the Jeep up front is a 39lb Warn Rock Crawler Bumper, 60lb winch, Front upper and lower CA's, and the MML (Motor Mount Lift)'s, minus the stock bumper weight. 🤨
Click to expand...
This is strange to me. I'm running the HD OME fronts and I get exactly 2" of lift, no spacers. I have a big steel bumper, winch, and a synthetic rope. Running the LD rears, and with my soft top, I also get 2" of lift. I have a steel bumper and run a spare. If I put the hard top on, I lose about a 1/4 inch.
 
bobthetj03 said:
@JMT, measure from the bottom of the frame where the rear lower control arm mount is welded to the forward part of the frame to level ground. You can do the same at the front lower mount. Those measurements should be pretty consistent amongst our TJ's/LJ's.
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@bobthetj03 and @Mike_H

Front = 17 3/4” (right behind the control arm bracket at the frame)
Rear = 18” (right in front of the control arm bracket at the frame)
 
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Fargo said:
I'm going to recant what I said above. Thinking about your Jeep, I think you are so light in the back, that the JKS springs might raise the rear so much that you might still need a 1" or more spacer in front. If you install JKS springs you are increasing both the front and rear spring rate. So you could end up in a similar situation as you are know. As much as I love my JKS coils, I think you are better off to just get the OME 934 for the front of your Jeep.
Click to expand...
I agree, keep the rear OME’s and go with the 2934 or something up front, bc those OME fronts aren’t more than 1.5”.

But let’s be honest, OME are advertised as 2”, and I think that’s with the 10mm spacer. Actually, I don’t know. But I do know mine are way short. 🤣
 
what is the consensus on this kit?

Looking at the 3" for my LJ.
 
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