Need help comparing springs (JL to JK)

[Jeepjunkie]

long story but I want to run Synergy springs... trouble is my PR44 can’t run the JL springs (Synergy swaps out the plastic lower perch, but that perch is metal, “indexed”, and welded to the PR44). So to run synergy springs they recommend JK springs.

Th JL “-20” spring is longer (20.75-21.25”) than the JK “-20” spring (19.53”). Tables below.
The JL spring rate is 110/120 and the JK is 131/155 (for -20).
The Jk “-30” is the right length unloaded (21.5”) but with a much higher JL “-20” spring rate (114/155).

I’m thinking I should go with the JK -30, even though the spring rate is higher. I really want 2” of lift and not a lot more. I have 2” spacers now with the perfect set up, except my articulation is limited when wheeling.
Thanks in advance.

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[Jeepjunkie]

Update, spoke to Synergy and will go with the JK -30 springs. Will post results after (may be weeks from now).

 

[sierrarockcrawler]

Update, spoke to Synergy and will go with the JK -30 springs. Will post results after (may be weeks from now).

FYI......The cast lower spring perch that Dynatrac uses can be ordered separately. It is held on by 3 bolts from the bottom that have a tack weld on them that would need to be cut off. I have been having problems with JL 3.5" Metalcloak springs unseating and twisting on my XD60 front axle which uses the same spring perch as the PR44. My plan is to cut off the small tab on the dynatrac spring perch then fill in the groove with JB Weld or similar product that can be machined when cured, then machine or grind the surface flat in order to run the synergy closed bottom coil springs. I ordered replacement perches from Dynatrac just in case I screw up!

 

[Jeepjunkie]

FYI......The cast lower spring perch that Dynatrac uses can be ordered separately. It is held on by 3 bolts from the bottom that have a tack weld on them that would need to be cut off. I have been having problems with JL 3.5" Metalcloak springs unseating and twisting on my XD60 front axle which uses the same spring perch as the PR44. My plan is to cut off the small tab on the dynatrac spring perch then fill in the groove with JB Weld or similar product that can be machined when cured, then machine or grind the surface flat in order to run the synergy closed bottom coil springs. I ordered replacement perches from Dynatrac just in case I screw up!

Thank you.
One thought I had was to add a retaining clip to hold the spring onto the lower perch. That’s what my modded TJ had and kept the spring from unseating during flex.

 

[AllJumpStyle]

Just keep in mind that our JK coil springs lift the vehicle differently than our JL springs. Our 3" JK springs are closer to 4" on a stock JK. Once you add bumpers, winch, skids, sliders, full-size beadlock spare, etc, you will be closer to 3".

The problem seems to be that most of the aftermarket axle housing companies are just using their existing JK coil spring perches instead of designing new ones similar in design to the JL flat ones. We're trying to see if we can come up with an "easy" solution to let our JL coil springs work with these axle housings.

 

[sierrarockcrawler]

Thank you.
One thought I had was to add a retaining clip to hold the spring onto the lower perch. That’s what my modded TJ had and kept the spring from unseating during flex.

A retaining clip was my first thought too, just hard to figure out how to attach on my axle. I really like the idea of the closed bottom coil and corner specific rates on the Synergys though, so I figured I'd give it a shot. I am going to run the 4" coils with probably a 1/2" spacer in the front, I will be installing a set of Teraflex IR longarms at the same time so that should help prevent as much axle movement at full droop.

 

[Jeepjunkie]

A retaining clip was my first thought too, just hard to figure out how to attach on my axle. I really like the idea of the closed bottom coil and corner specific rates on the Synergys though, so I figured I'd give it a shot. I am going to run the 4" coils with probably a 1/2" spacer in the front, I will be installing a set of Teraflex IR longarms at the same time so that should help prevent as much axle movement at full droop.

If you don’t mind posting your results, please do. I also really like the synergy JL springs for all the reasons you outlined.

 

[Jeepjunkie]

Just keep in mind that our JK coil springs lift the vehicle differently than our JL springs. Our 3" JK springs are closer to 4" on a stock JK. Once you add bumpers, winch, skids, sliders, full-size beadlock spare, etc, you will be closer to 3".

The problem seems to be that most of the aftermarket axle housing companies are just using their existing JK coil spring perches instead of designing new ones similar in design to the JL flat ones. We're trying to see if we can come up with an "easy" solution to let our JL coil springs work with these axle housings.

Thank you Chris.

I have been emailing back and forth with Calvin at Synergy. He’s been super helpful. Given my current set up (2+ inch spacers up front, heavy bumper & winch & armor, and a PR44) we thought trying the JK-30 springs was worth try (I also want an inch or 2 more than I get with the 2” spacers). Worst case, I send the -30s back to Quadratec and get the -20 springs for the JK. I don’t mind wrenching extra, it’s half the fun.

 

[sierrarockcrawler]

If you don’t mind posting your results, please do. I also really like the synergy JL springs for all the reasons you outlined.

Will do. It will probably be 3-4 weeks before I can get everything installed.

 

[Halstem1]

Curious of your results when you're done. Please post an update when complete. I've been looking for a higher spring rate for towing. I'd have to ask someone that knows more than me, but the JK springs could be a good fit. However, unsure what that would do to the front. and I'm assuming you would want the springs to match front and rear. I remember when Lite Brite installed their hemi, they switched to a JK spring to offset the weight.

 

[Jeepjunkie]

Curious of your results when you're done. Please post an update when complete. I've been looking for a higher spring rate for towing. I'd have to ask someone that knows more than me, but the JK springs could be a good fit. However, unsure what that would do to the front. and I'm assuming you would want the springs to match front and rear. I remember when Lite Brite installed their hemi, they switched to a JK spring to offset the weight.

Will do. The springs arrived today and if it’s ever stops raining and my fingers aren’t frozen off, I’ll install them soon.

FYI that I’m only doing JK front springs. I have JL rear springs coming (on backorder). For now I’ll use spacers for the rear until the Synergy rear JL springs get delivered.

 

[lembowski]

I ordered my 3” synergy springs last week. All the online vendors said backordered so I called Poly Performance (Synergy & Poly same owner) and they had them in stock and I received them next business day.

 

[Jeepjunkie]

Follow up and info for anyone with a PR 44 wanting to run Synergy JK springs (the Synergy JL springs are flat-bottomed, and won’t fit into the “indexed” metal lower spring perch). I installed JK 8063-30 springs on my JLUS today.

I have about 150# of bumper, winch and armor on the front. I started the day with Rubicon springs and a 2” spacer. I swapped those out for Synergy JK 8063-30 springs. Those -30 JK springs gave me an additional 2-2.5” of lift on my JLU (give 3” on a JKU) compared to the Rubicon springs + 2” spacers.

Now I just need the rear Synergy JL springs, which Qtech still has listed as backordered. I might do what Lembowski did and order direct. For now I added another 1” to the rear with spacers. Here she is:

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