Should I replace my springs after going from soft top to hard top?


GoldenEagle

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Hey folks,

Long time lurker, first time poster and member.

I have been digging for a minute about springs and hard tops on this forum, but haven't found the info I need. I have some progressive RCs after a lift on my 06 Golden Eagle edition TJ. It was born a soft top, soft top 4" springs are what I got when I lifted it in April. I decided the soft top needed to be replaced, along with the bows. Since I pull the full top completely off every spring and run a safari top, I figured why replace that for half the cost of a used hard top.

Here we are. Soft top progressive springs with a hard top. Should I swap my rear springs?

Do I notice a difference? Yes. Mainly on road around town. This is my DD, so it is annoying. But, I can live with it for 5 or 6 months at a time since I work from home now and don't drive too much. My real question is, should I replace springs to save something else like shocks or anything else?
 

jjvw

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The change in ride height from the addition of a hardtop is roughly the difference between an empty and a full tank of gas. Do you feel the need to change springs when you leave the gas station?
 
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GoldenEagle

GoldenEagle

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The change in ride height from the addition of a hardtop is roughly the difference between an empty and a full tank of gas. Do you feel the need to change springs when you leave the gas station?
No, but now we're talking about two "tanks of gas," plus a steel bumper and tire carrier and an additional 90ish pounds of steel from a tuffy enclosure. Its not a ride height question. Its a question of whether I'm adding additional wear elsewhere keeping a lighter spring. Adjustable shocks may be what I really need, I don't know. All I know is there are different spring rates for a reason, and I have a hard time believing its just to sit more level.
 

jjvw

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No, but now we're talking about two "tanks of gas," plus a steel bumper and tire carrier and an additional 90ish pounds of steel from a tuffy enclosure. Its not a ride height question. Its a question of whether I'm adding additional wear elsewhere keeping a lighter spring. Adjustable shocks may be what I really need, I don't know. All I know is there are different spring rates for a reason, and I have a hard time believing its just to sit more level.
Your question has everything to do with ride height.
 
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Chris

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If it’s sagging, you could go with a heavier duty spring rate or a spacer in the rear.
 

JMT

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You're only talking a difference in weight of ~80lbs. Hardtop weighs 115lbs and soft top probably weighs 35 (that's a guess). There's no reason to change your springs for that difference at all. If you are that OCD, don't change anything on your rig, because every time you do weight adds up.
 
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JMT

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No, but now we're talking about two "tanks of gas," plus a steel bumper and tire carrier and an additional 90ish pounds of steel from a tuffy enclosure. Its not a ride height question. Its a question of whether I'm adding additional wear elsewhere keeping a lighter spring. Adjustable shocks may be what I really need, I don't know. All I know is there are different spring rates for a reason, and I have a hard time believing its just to sit more level.
Different spring rates just relate to ride height at a given length spring.

160 in lb spring will compress 1 in for ever 160lb you add to the sprung weight of the Jeep.

200 in lb spring will compress 1 in for every 200lb you add to the sprung weight of the Jeep.
 

cpwolf

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The change in ride height from the addition of a hardtop is roughly the difference between an empty and a full tank of gas. Do you feel the need to change springs when you leave the gas station?
Made my day, been a long and serious day at work and this was good, just had to say it....
 
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GoldenEagle

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Different spring rates just relate to ride height at a given length spring.

160 in lb spring will compress 1 in for ever 160lb you add to the sprung weight of the Jeep.

200 in lb spring will compress 1 in for every 200lb you add to the sprung weight of the Jeep.
Stiffer shocks is the solution for me then, I guess. With the hardtop on, its a lot more body roll. That's to be expected, more weight higher up. It just feels like way more than I would have anticipated.
 

Steel City 06

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Body roll won't be significantly changed by springs. Heavier or dual rate sway bars, and often sticks, will reduce noticed body roll.

As for sag due to weight, taller springs or stiffer springs will help. I run the Currie LJ springs on my TJ because of the extra weight of the tire carrier and expanded gas tank.

If you're frequently changing the load, airbags (like the Air Lift 1000 Universal) make it very easy to adjust the loaded height and level the car. I run these on my TJ as I am constantly adding or removing cargo.
 

jjvw

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Stiffer shocks is the solution for me then, I guess. With the hardtop on, its a lot more body roll. That's to be expected, more weight higher up. It just feels like way more than I would have anticipated.
My preferred configuration for the Jeep is the soft top and soft half doors. It rides the best like this as well. Just putting on the hard doors makes a noticable difference in the amount of roll the Jeep has. Mine has adjustable rear shocks where I can dial out much of this.
 

JMT

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Body roll won't be significantly changed by springs. Heavier or dual rate sway bars, and often sticks, will reduce noticed body roll.

As for sag due to weight, taller springs or stiffer springs will help. I run the Currie LJ springs on my TJ because of the extra weight of the tire carrier and expanded gas tank.

If you're frequently changing the load, airbags (like the Air Lift 1000 Universal) make it very easy to adjust the loaded height and level the car. I run these on my TJ as I am constantly adding or removing cargo.
Would the Air Lift 1000 help with keeping the rear of my Jeep level when pulling a trailer nearing the 2,000lb capacity of our TJ's? Does it just install within the coil spring?
 
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GoldenEagle

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My preferred configuration for the Jeep is the soft top and soft half doors. It rides the best like this as well. Just putting on the hard doors makes a noticable difference in the amount of roll the Jeep has. Mine has adjustable rear shocks where I can dial out much of this.
That's the ticket. I ditch the hardtop and steelies around May and would generally run soft doors and a bikini/tonneau setup until October. Winter came early and I needed a new top anyway.

Body roll won't be significantly changed by springs. Heavier or dual rate sway bars, and often sticks, will reduce noticed body roll.

As for sag due to weight, taller springs or stiffer springs will help. I run the Currie LJ springs on my TJ because of the extra weight of the tire carrier and expanded gas tank.

If you're frequently changing the load, airbags (like the Air Lift 1000 Universal) make it very easy to adjust the loaded height and level the car. I run these on my TJ as I am constantly adding or removing cargo.
Weight doesn't change significantly outside of the doors and top and maybe a cooler loaded down for hunting or camping. Looking to ditch my RC shocks anyway, so sounds like an adjustable shock is my best bet for stiffening up the rear end when I need to.
 
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JMT

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so sounds like an adjustable shock is my best bet for stiffening up the rear end when I need to.
Stiffening up in what way? Shocks won't do anything for sway and they won't hold the Jeep up, springs do that. Just not following exactly what you are trying to accomplish.
 

Steel City 06

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Would the Air Lift 1000 help with keeping the rear of my Jeep level when pulling a trailer nearing the 2,000lb capacity of our TJ's? Does it just install within the coil spring?
Absolutely. It reduces the squat of the vehicle due to load, and is 100% adjustable. Simply run a very low PSI (usually 5 PSI) unloaded, load it up, and add air (up to 35 PSI) to level it. I found I can compensate for about 600 additional lbs or so on the rear axle with the bags.

Assuming you have some sort of lift coil, you'll need to measure the inside height and diameter and order the airbag kit that fits. You'll want a full height airbag for best results, meaning you'll need to remove the upper and lower bumpstop assemblies, if equipped.

I addressed some of my experiences and lessons learned in the last post on this thread:

I chose to plumb mine individually so I could level side to side and reduce body roll. You can also plumb them to a tee for simplicity.

I also added airbags to the front coils, but that was far from necessary.

I made the mistake of using partial height airbags in the rear sorings the first time. Replacing them with full height bags snd removing the bumpstop cups and assemblies more than doubled the lifting capacity on the rear axle.

Front airbag:
20200916_191645.jpg

Rear airbag:
20200916_191657.jpg

Makeshift Schrader valve manifold:
20200916_191813.jpg

These are all on a Savvy 4" lift with the LJ rear coils (on a TJ).
 
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JMT

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Absolutely. It reduces the squat of the vehicle due to load, and is 100% adjustable. Simply run a very low PSI (usually 5 PSI) unloaded, load it up, and add air (up to 35 PSI) to level it. I found I can compensate for about 600 additional lbs or so on the rear axle with the bags.

Assuming you have some sort of lift coil, you'll need to measure the inside height and diameter and order the airbag kit that fits. You'll want a full height airbag for best results, meaning you'll need to remove the upper and lower bumpstop assemblies, if equipped.

I addressed some of my experiences and lessons learned in the last post on this thread:

I chose to plumb mine individually so I could level side to side and reduce body roll. You can also plumb them to a tee for simplicity.

I also added airbags to the front coils, but that was far from necessary.

I made the mistake of using partial height airbags in the rear sorings the first time. Replacing them with full height bags snd removing the bumpstop cups and assemblies more than doubled the lifting capacity on the rear axle.

Front airbag:
View attachment 190336
Rear airbag:
View attachment 190337
Makeshift Schrader valve manifold:
View attachment 190338
These are all on a Savvy 4" lift with the LJ rear coils (on a TJ).
You are a God-send. Very thorough and helpful.
So I’ll remove the jounce, the cup, and the rest of the upper assemble, measure width and height at ride height for the air bag, then order the bag that fills the space. When I’m not needing them, just let the air out? No need for bumpstops and all that? Cycle the suspension to see minimal pressure in the bags?

Thank you,
JMT
 
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jjvw

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You are a God-send. Very thorough and helpful.
So I’ll remove the jounce, the cup, and the rest of the upper assemble, measure width and height at ride height for the air bag, then order the bag that fills the space. When I’m not needing them, just let the air out? No need for bumpstops and all that? Cycle the suspension to see minimal pressure in the bags?

Thank you,
JMT
When I built my AirLift bag system, I kept the jounces in place and found a bag that fit in between the axle pad and jounce when deflated.
 

Steel City 06

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Yeah you can do it either way. If you're doing hard-core offroading, it may be better to keep the bumps in place like @jjvw did. If most of your stuff is slow moving and you're not concerned about using the shocks to limit travel, a full height airbag would be a better option.

I think I got about 300 lbs of leveling with the original bumpstops in place, and about 700 lbs with the full bags. This was measured directly over the rear axle. Weight further out, like tongue weight or tire carriers will have a magnified impact.

This is the chart you'll need to use to select a kit:
1600304033390.png

You'll want to match the height as close as possible. The kits come with 2 pairs of 1/2" spacers, so you can adjust the height without too much difficulty.

With the Currie/Savvy 4" lift, I used the 60921 kit. If you have less than 4" or want to keep your bumpstops, you will need a shorter airbag.
 
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JMT

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When I built my AirLift bag system, I kept the jounces in place and found a bag that fit in between the axle pad and jounce when deflated.
Did you remove after intermittent use of the air bags?