Shock, Springs & Suspension Information Chart Matrix

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AnnDee4444

AnnDee4444

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Andy, not sure if I'm doing something wrong, but on the Shock Matrix section it won't scroll and only goes down to halfway into the Bilstein 1.5-3" shock. Was interested in some Teraflex data if you happen to have that on the list :)
Try it now. If it doesn't work, let me know what browser you're using.

Sorry, no Teraflex shocks yet.





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blnewt

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Try it now. If it doesn't work, let me know what browser you're using.

Sorry, no Teraflex shocks yet.
Still not scrolling, I'm on Firefox
 

Trill

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You need to click the google docs link not the image preview
 
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AnnDee4444

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Good work. If you're up to it, you could also use geometry to give people who buy adjustable track bars with their lift kits a starting point for what length they should be shooting for.

track.png


A is track bar length eye to eye. B and C are imaginary lines. As C (lift) increases, B (lateral axle placement underneath the jeep) will shrink, causing the axle to be pulled to the side. (A) would need to be extended to some variable depending on C to keep B the same as stock. Could also factor for the common raised track bar bracket heights.
That shouldn't bee too hard to calculate, but I'm not sure that all the frames are all 100% identical... given the factory tolerances. I'll give it a shot when I have some free time to measure.

What I'm really interested in calculating is the pinion/caster angle vs. suspension height. That's always been a mystery to this forum... like how much the Mopar LCAs will increase the caster at specific lift heights.

FWIW: if anyone can fit the (axle side) track bar relocation brackets, I would try that before an adjustable track bar. I've had great results when raising the roll center on other vehicles, and I suspect the JL will respond nicely also. Obviously there are other reasons to replace the track bar, but in my opinion you should consider the roll center first, then center the axle under the body.
 

blnewt

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Thanks, working now!
 
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AnnDee4444

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Front:
At full bump, there is 16.25" between upper and lower shock mounts.
At full extension, the spring begins to lose pre-load at 26.25" between upper and lower shock mounts.

Rear:
At full bump, there is 17" between upper and lower shock mounts.
At full extension, the spring begins to lose pre-load at 27.75" between upper and lower shock mounts.
I finally found a place to flex my stock JLR, and decided to take some measurements to see how close I could get to the theoretical limits you found.

Front:
  • Bump measured around 16.5", which is pretty close to the 16.25" you measured
  • I'm on stock Rubicon shocks, had them fully extended (23.625")
Rear:
  • Bump was only able to get to 18.5" (vs. your 17"). The Rubicon shocks are only 17.5" compressed, so I was really only 1" away from bottoming out the shock. The bump stop was compressed, but I don't think I have enough weight to fully compress them with my unloaded no-backseat 2-door. When actually driving over terrain, I don't doubt that it could compress another 1".
  • Stock Rubicon shocks again, had them fully extended (26")
 

Trill

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I finally found a place to flex my stock JLR, and decided to take some measurements to see how close I could get to the theoretical limits you found.

Front:
  • Bump measured around 16.5", which is pretty close to the 16.25" you measured
  • I'm on stock Rubicon shocks, had them fully extended (23.625")
Rear:
  • Bump was only able to get to 18.5" (vs. your 17"). The Rubicon shocks are only 17.5" compressed, so I was really only 1" away from bottoming out the shock. The bump stop was compressed, but I don't think I have enough weight to fully compress them with my unloaded no-backseat 2-door. When actually driving over terrain, I don't doubt that it could compress another 1".
  • Stock Rubicon shocks again, had them fully extended (26")
We might need to revisit the rear rubi shock compressed length. 17.5" would be an unusually tight tolerance for an OE application. I know its hard to get an accurate compressed measurement of a gas charged shock since it's always fighting you. But I just can't see 17.5" being the case.

Going back to my measurements, I did measure 17" max compressed length in the rear under ideal circumstances (no coil springs, no bump stop pads, full metal-on-metal bump on both sides) but it was also slightly awkward to get a perfect measurement with a tape measure, so I measured slightly conservatively. It might be slightly more, maybe 17.5" max?

At any rate, the fox shocks I ordered for the rear have a 16.75" compressed length. You can see how little shock shaft I have showing. What I don't know is if Fox's specifications for compressed length include or exclude that 1/4" rubber bump pad. With that removed, I would estimate there would be 1/2" - 3/4" of shock shaft exposed at full bump. Bringing max compressed length to somewhere around 17.25" - 17.5" depending on factory manufacturing variances. This is why I doubt the 17.5" factory rubicon shock measurement.

fox_rear_bump.jpg


If we turn to the front for reference, I measured 16.25" fairly accurately, and ordered Fox shocks with exactly that compressed length. You can see that I am fully compressed into that rubber bump pad on the shock. So based on that I would suspect that Fox advertises their compressed lengths inclusively with the bump pad.

fox_bump_front.jpg
 
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AnnDee4444

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We might need to revisit the rear rubi shock compressed length. 17.5" would be an unusually tight tolerance for an OE application. I know its hard to get an accurate compressed measurement of a gas charged shock since it's always fighting you. But I just can't see 17.5" being the case.

Going back to my measurements, I did measure 17" max compressed length in the rear under ideal circumstances (no coil springs, no bump stop pads, full metal-on-metal bump on both sides) but it was also slightly awkward to get a perfect measurement with a tape measure, so I measured slightly conservatively. It might be slightly more, maybe 17.5" max?

At any rate, the fox shocks I ordered for the rear have a 16.75" compressed length. You can see how little shock shaft I have showing. What I don't know is if Fox's specifications for compressed length include or exclude that 1/4" rubber bump pad. With that removed, I would estimate there would be 1/2" - 3/4" of shock shaft exposed at full bump. Bringing max compressed length to somewhere around 17.25" - 17.5" depending on factory manufacturing variances. This is why I doubt the 17.5" factory rubicon shock measurement.

fox_rear_bump.jpg


If we turn to the front for reference, I measured 16.25" fairly accurately, and ordered Fox shocks with exactly that compressed length. You can see that I am fully compressed into that rubber bump pad on the shock. So based on that I would suspect that Fox advertises their compressed lengths inclusively with the bump pad.

fox_bump_front.jpg
To be honest, I haven't actually measured the shocks myself and instead relied on the forum for numbers. Either way your logic and process looks good to me, and I'm going to use your numbers for future calculations.

Right now my plan is to run 35s or 315/70-R17, which I think will need a 1/2" bump stop extension (I know people do it all the time with OEM bump stops, but I have read that there is some light rubbing), along with a 1-1.5" spacer lift. What's interesting about Fox's line up, is that a 1/2" extra bump stop should allow the use of their 2"-3" lift shocks. Front shock 885-24-183 is 16.45" compressed, and rear shock 985-24-184 is 17.35" compressed. This should allow for slightly more travel in the front, and close to 2" more shock travel in the rear than using the 0-1.5" Fox shocks.
 

Trill

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Right now my plan is to run 35s or 315/70-R17, which I think will need a 1/2" bump stop extension (I know people do it all the time with OEM bump stops, but I have read that there is some light rubbing), along with a 1-1.5" spacer lift. What's interesting about Fox's line up, is that a 1/2" extra bump stop should allow the use of their 2"-3" lift shocks. Front shock 885-24-183 is 16.45" compressed, and rear shock 985-24-184 is 17.35" compressed. This should allow for slightly more travel in the front, and close to 2" more shock travel in the rear than using the 0-1.5" Fox shocks.
35s are tough that's for sure at least in the rear. I have a sport, but it has rubi axles, rubi fenders, and rubi rear bumper so our applications with respect to tire fitment will be the same. I had the benefit of adjustable control arms in the rear to dial in fitment with 35s. Wheel position forward and back (control arms), and in and out (wheel offset) is critical. Stock wheels are mandatory, I can't imagine this working with any changes to wheel offset. With longer rear shocks we have more rear steer and more wheel inclination while articulated which also complicates this. They still rub under ideal circumstances, cycling the suspension in your garage without coil springs. But it is what I consider an acceptable rub, no fender deflection or any edges being caught. In the real world with the rear sway bar connected you have a bit more breathing room. The front has more room and it's just a gentle kiss up there. Adding 1/2" bump stop would make this fitment significantly easier. And because of variations in true tire radii and factory tolerances it is impossible to say what works and what doesn't, everyone just needs to do their own experimentation and make adjustments as necessary.

Your suspension numbers look 100% on-point. Spending the extra money on the remote res model is a great idea, it takes the floating piston out of the main shock body and frees up a ton of travel without much of any compressed length penalty. If I tried to use those rear shocks, I can tell you that my rear coil springs would be laying on the ground the first time I flexed over an obstacle. But I think you have that problem covered. The extra free length of the rubicon coil springs (compared to a sport) in conjunction with the 1.5" coil spacer should keep your rear coils pre-loaded at full droop. The rear motion ratio does complicate this though so it's worth giving those rear coils a tug and making sure they aren't going anywhere.

Ultimately you will end up with more than 10" of wheel travel in the front, more than 13" in the rear, getting every penny of shock stroke that you paid for, and only needing a 1.5" coil spacer and 0.5" bump stop. You better keep this tight lipped or the lift kit cartel is going to come after you! :bandit:
 
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ossme

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Please excuse my noob question but, wouldn’t installing 1.5" spacer lift require an equal 1.5" bump stops? What am I missing?
 
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Please excuse my noob question but, wouldn’t installing 1.5" spacer lift require an equal 1.5" bump stops? What am I missing?
Ride height is determined by the amount of spring & spacer installed.

The bump stops should only used for making sure the tire or shock doesn't bottom out.
 

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Thank you, AnnDee.

So, I understood that, with 1-1.5" spacers, The OEM rubicon springs would not fully compress even at full bump?

If my assumption is correct, then that is great news for me personally. :)
 
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AnnDee4444

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Thank you, AnnDee.

So, I understood that, with 1-1.5" spacers, The OEM rubicon springs would not fully compress even at full bump?

If my assumption is correct, then that is great news for me personally. :)
I'm not sure if the Rubicon springs can compress an extra 1.5". If they can't, then you'll never hit the bump stop anyway.
 

CptFloridaMan

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I've had a few people ask for access to my shock & spring charts, so I decided to put all this in a sharable format that anyone can access or download & modify. There's more than one tab at the bottom, feel free to view or download.

Shock Matrix
The following fields highlighted in yellow are adjustable.
  • The 'Ride Height' field uses my JLR as a base, but your Jeep may ride differently. Be sure to check the shock eye-to-eye measurements for accuracy.
  • 'Bump Travel' (or Up Travel) just turns some of the text red that is outside of the recommended range
Capture.PNG



OEM Springs: a never complete list of all the spring combinations

2.PNG


Rear Motion Ratio: shows how the rear shock's response isn't linear to suspension travel, and most important at lower ride heights

Spring Rates: a small list of spring rates I have collected from this forum

Caster: another small list, this time of caster measurements using fixed arms

Wheelbase: comparing the JL to other Jeeps

Breakover: how the JL & JT breakover angles change at various heights

Man this is amazing! Ive been referring to the screenshots of your spreadsheet in various threads but never knew of the full thing. Ive been gathering my own data but this trumps it. :clap:

I notice some shocks that are similar to stock compressed length are marked as red. What makes it outside of the recommended range? For ex. fox 2.5 dsc 0-1.5” of lift.
 

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