Synergy Long Arm Clearance Question

Noble Woodsman

Noble Woodsman

New member
I may be going down a rabbit hole here, but I'm having trouble understanding the backspacing recommendation from Synergy for their stage 4 long arm kit (3" or 4/4.5"), and I am hoping someone running this suspension can help me visualize this.

Synergy recommends a maximum backspacing of 4.75" with these LA kits to run 37x12.50R17 tires. I reached out to them to ask about this number, and and was told "our recommended backspacing is to clear the longer rear sway bar links and high steer drag link". Best I can tell from reviewing install videos, pictures, and the installation manuals, the rear sway bar links and high steer drag link/bracket seem to be the same dimensions as those found on the AEV DualSport 4.5" lift, which recommends up to 5.2" backspacing for the same tires. Would someone with the Synergy LA kit please post a picture of your setup showing the clearance between (1) the tires and rear sway bar links and (2) the tires and high steer drag link to help me understand what I'm overlooking? Please note what tire size and backspacing you're running for reference.

Ideally, I'd like to run a BS of 5.2" (or anything larger than 4.75") with the Synergy LA kit to help reduce strain on the stock axle wheel bearings, and I want to see proof that it won't work before I completely rule this out. Thank you!
 
More backspacing pulls the tire closer to the axle instead of out and away from any components.


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With the 37s on stock width axles, you will rub the frame at full lock when turning. I ended up running 1.5” spacers to eliminate that with 4.5” back spaced wheels. I did clear the sway bar links.

I do still run the AEV 4.5” springs and stock fenders and they barely clear there the 37 BFG KM2s.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
 
wjtstudios said:
With the 37s on stock width axles, you will rub the frame at full lock when turning. I ended up running 1.5” spacers to eliminate that with 4.5” back spaced wheels. I did clear the sway bar links.

I do still run the AEV 4.5” springs and stock fenders and they barely clear there the 37 BFG KM2s.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
Click to expand...

This is exactly why I am confused. I would expect the same arrangement you have to also fit the synergy kit, but your setup is equivalent to a 17x8.5 wheel with 6" of backspace (1.5 + 4.5), so why would Synergy recommend a maximum of 4.75" then? Is there something different between the synergy and evo LA kit clearances?


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Noble Woodsman said:
This is exactly why I am confused. I would expect the same arrangement you have to also fit the synergy kit, but your setup is equivalent to a 17x8.5 wheel with 6" of backspace (1.5 + 4.5), so why would Synergy recommend a maximum of 4.75" then? Is there something different between the synergy and evo LA kit clearances?


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Click to expand...

Opposite actually. 4.5” minus the 1.5” so affectively I was running 3” of backspacing. Does that make sense?


2015 JKUR AEV JK350
1985 CJ8 Scrambler
 
Noble Woodsman said:
This is exactly why I am confused. I would expect the same arrangement you have to also fit the synergy kit, but your setup is equivalent to a 17x8.5 wheel with 6" of backspace (1.5 + 4.5), so why would Synergy recommend a maximum of 4.75" then? Is there something different between the synergy and evo LA kit clearances?


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Click to expand...

You have it backwards... it would be 4.5 - 1.5. So he’s running 3” backspacing.

Edit: beat me to it. Lol

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I don't have the long arm kit, but do have a comment.

If you wheel in challenging places, having the wider track from less back spacing or adding spacers helps with stability to make off camber situations easier to tackle without getting tippy.

Other things come into play, but I like to be wide.
 
Thanks guys! Yes, subtracting the wheel spacer thickness instead of adding it makes sense.

This also clarifies my original question... AEV recommends a 1" wheel spacer if using stock wheels with the dualsport lift, which would be equivalent to 4.5" BS, and is consistent with most lift manufacturers recommendation, including synergy. AEV does offer a 5.2" BS wheel, but from what i can tell, most people use this wheel for 33" or 35" tires, not true 37". I guess with 37" tires, 4.5" BS still causes rubbing with factory flares.


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jdofmemi said:
I don't have the long arm kit, but do have a comment.

If you wheel in challenging places, having the wider track from less back spacing or adding spacers helps with stability to make off camber situations easier to tackle without getting tippy.

Other things come into play, but I like to be wide.
Click to expand...

Agreed. I plan to upgrade to wider axles in the future, but in the meantime i will be upgrading to 35s on stock rubi axles and weighing 6000 lbs, so my immediate concern is reducing the maintenance required on the wheel hubs by keeping as large an offset as possible. This means narrow wheel and as large BS as possible.

P.S. I know a LA suspension upgrade is overkill for 35s, but i'm building it now to eventually run 40s. When that time comes, i figure i will only need to replace coils and shocks on the suspension, which will make that upgrade cheaper and easier.


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Noble Woodsman said:
Thanks guys! Yes, subtracting the wheel spacer thickness instead of adding it makes sense.

This also clarifies my original question... AEV recommends a 1" wheel spacer if using stock wheels with the dualsport lift, which would be equivalent to 4.5" BS, and is consistent with most lift manufacturers recommendation, including synergy. AEV does offer a 5.2" BS wheel, but from what i can tell, most people use this wheel for 33" or 35" tires, not true 37". I guess with 37" tires, 4.5" BS still causes rubbing with factory flares.


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Click to expand...

You will still have some rubbing with the factory flares, and depending on which tires you run, you may have more than I experienced. I kept my extended AEV bumps in place to limit how much contact I made.

I’m not familiar with the synergy kit, but my only complaint with the EVO kit is that the rear lower control arm mounts at the frame like to get hung up on rocks with 37s. I’m hoping to gain a bit more room with 40s. My only regret was not trying to work thru the challenges of getting the high clearance LA kit to work. So keep that in mind as well with 35s.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
 
wjtstudios said:
You will still have some rubbing with the factory flares, and depending on which tires you run, you may have more than I experienced. I kept my extended AEV bumps in place to limit how much contact I made.

I’m not familiar with the synergy kit, but my only complaint with the EVO kit is that the rear lower control arm mounts at the frame like to get hung up on rocks with 37s. I’m hoping to gain a bit more room with 40s. My only regret was not trying to work thru the challenges of getting the high clearance LA kit to work. So keep that in mind as well with 35s.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
Click to expand...

What are the challenges? I am considering that kit


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wjtstudios said:
Bubba from exodus can explain it best, but the axle portion of the mounts need to be reworked. The kit was originally created to work with the DTD.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
Click to expand...

Speedy_RCW said:
You have to fab up a lower shock mount. The factory control arm mount is also the shock mount and gets cut off with the EVO kit.


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Click to expand...

I think there is a new high clearance kit that deals with this. EVO-1200.


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wjtstudios said:
Damn, wish that was out when I did mine.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
Click to expand...

Nice huh? :mad:

Went over this with Bubba. Not sure the cost to remove brackets and reinstall the high clearance versions would be worth the cost? I thought of getting "ramps" welded onto the frame rails so the transition to the mounts wasn't as abrupt.
 
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