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Trying to think through front spring options

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Well that's a little give and take. Softer springs are going to be more compliant which means that on a compression stroke, they transfer less energy to the chassis and keep more rubber on the road but the opposite is true for extension as they are slower to respond. Really the range of acceptable firmness is insanely wide and what you posted is more appropriate for a car than a pickup where spring rate has a lot more responsibility such as the towing and plow cases.

So I guess what it comes down to is suck it up or buy another truck haha. You unfortunately have a multi-use scenario that requires opposing strategy and there's just no way around that. You aren't increasing rate enough here that it will really change handling but you will see changes in ride. It's just the nature of the beast when setting a truck up for both unladen daily driving and loaded work duty.
It's going to be a compromise, no matter what. Can't get around that. My F250 rode like a, well, like a truck, my mother would have said "lumber wagon" or maybe "hay rack". But add 2,000+ pounds in the back and it was a Cadillac for ride. Then the weight matched the spring rate better. My first flat bed on the back it really smoothed that truck out.
This is just the opposite - it starts with good street personality and behavior, good ride, but those times it's loaded, have to compensate.
Multi-rate makes sense - we have max tow to refer to there. It would seem that taller springs with only a slightly higher rate might work - more stored energy, when compressed, still high enough.
The Rubicon springs under the front of my 2020 actually did well as far as handling on the road.
They were the lighter of the Rubicon pairs so it made sense they dropped with the weight of the steel bumper, etc. So I had to use spacers to get the height back up again.......leaving less spring travel.

I suspect maybe a phone call to Synergy may be in order. They don't respond to email.

We were fine with the ride the 2020 had after the mods I made on it - even though the rear was a bit stiffer (max tow springs) the front was nice and took bumps and tracks fine. And it was solidly planted.

As is not unusual, you present another "voice of reason"
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Checked some specs -
JLU Rubicon base curb weight is right around 4500 pounds. (4450 or something like that)
JT Overland base curb weight is right around 4700 pounds (Iowa says it's 4500 pounds)
Rough figures, 200 pounds difference, maybe 250.
The front ends of each are basically the same configuration, if a JLU Rubicon has the sway bar disconnect, then it's got some added weight up front, bigger tires, etc. so the fronts could be heavier on the JLU Rubicon end of things.
The extra weight of the gladiator is going to be the box, tail gate, rear frame weight and so on.
Almost all of the JT frame's extra length and box are behind the rear axle. I'd say 2/3 of the box is behind the rear axle.
So weight up front is likely to be almost a wash.
Only way to know would be put each on a scale..............
.......I have to question how much difference there is on the front axle as far as JLU Rubicon vs. JT Overland (base configurations
 

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One reason I want to try to stay with springs with a rate to match the truck weight is to keep the tires planted. Using stiffer springs to hold the truck up higher is problematic for keeping the tires in contact with the road. You want the springs to compress some with the weight so if your tires hit a hole and drop, the spring can uncompress and push the tire down. If it's not compressed enough, the tire loses contact and the truck drops into the hole.

Stiffer isn't better on the street, or even some off-roading.



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I can see that's where they'd work - for when the plow was raised and full weight was on the truck.
That makes sense. An overload with the plow raised, otherwise a nicer bump stop.
Your theory on not using too little or much spring is exactly what using those Synergy springs is doing? A super tall light spring to maintain height.......Essentially a ton of preload. The reason they require so much bump stop spacing is because the block height is so high due to the number of coils vs height. Desert racing is different than daily driving, which is different from towing/plowing, which is different from rock crawling.

The key here is "enough" rate to hold up the truck without excessive body roll and offers enough support for intermittent loads. Then introduce the correct amount of damping from the shocks to keep the tires on the ground and control bottoming.
 
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The springs I've been looking at are dual rate. (similar to the max tow rears - lower rate for ride, then when pressed you get into the higher rate to support the weight)
They have a higher secondary rate than my current springs.

I spoke with two people - one at Synergy, another at Poly Performance.
Both said that the springs would give me about 1.5" as my truck sits now.
They also said with the weights I was talking (and I was specific) I'd end up with 1 to 1.25" of lift.
The guy at Poly knew these springs well - and said they've been successful on Gladiator and didn't have to look anything up.

The bump stop extension is assuming you'd be running much larger tires and would prevent dropping so far as to get into the tires.
I wouldn't need them (unless I got into shocks that might "bottom out" on full compression)

I mentioned my experience with the Rubicon springs and how those dropped a full 1/2" when I added the steel bumper and winch and they said - these won't drop that much. That indicates that secondary rate has to be a bit higher than Rubicon springs.
These aren't linear rate springs like stock springs, or like most other lift springs.
 
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As a "PS" - I'm going to try with the stock shocks since those are made for the tall but low rate stock Overland springs.
I'm assuming if those don't do well I'd have to have something akin to shocks used in drag racing - dampen on the down, allow a quicker up, but we'll see how it works out.
I'm not sure how much range the stock Overland shocks have as far as up-travel - I had Rubicon shocks on my 2020 when it was sitting about an inch to inch and a quarter higher. Are they different length than the Overland shocks? I never compared! Normally I do such things but never thought about it last time.
 

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2022 Overland. Will be putting my steel bumper, skid plate and winch back on. (had them on my 2020)
That will add about 150 pounds to the front.
My 2020 had the lighter number Rubicon front springs under it.
Left front - 339
Right front - 340
Those gained about 1" up front when the truck was otherwise stock.
When I put the winch and bumper on, it dropped about .5"
I then added Daystar 3/4" spacers to bring it back up for a net gain of roughly 1.25"

The 2022 Overland has very different spring numbers under it - so if the current Overland springs are stiffer, that means these light Rubicon springs won't gain me as much. There's no way I know of to compare the 2022 front springs to the 2020 front springs.

Another twist in the road - I'm likely to get a snow blade for the JT this fall...............

I want to:
  • Keep the ride this truck has as much as possible
  • Add the bumper, winch and skid plate
  • Have a net gain in height of roughly 1.25" on the truck after the bumper/winch, etc. are added.
  • Have the truck not drop to the ground with a blade on it for winter.

I'm just thinking that the current light numbered Rubicon springs aren't going to do it.
No way I can go with 2" or higher lift - not with my wife already complaining getting in and out with bad knees and such. Almost every "lift" is advertised as at least 2" and we know that it ends up being over 2" if you read all the posts from people that use a so-called 2" lift on anything except Rubicon.
Going over about 1.5" means more parts, centering the axle, making up for caster loss and so on.
PLUS - the expense involved of a lift is just not possible. I went the Rubicon spring and Daystar spacer route because it was a mere fraction of any other way - and frankly, the Rubicon springs really didn't change the way the front of the truck handled rough roads.

So looking for ideas, maybe things I have not considered (very possible) and doable for under 400 bucks or so (I don't have that much in the spacers and these lighter Rubicon springs) 300 would be closer.
Why do you say the Rubicon had lighter springs? I've never heard this or read into it. Do they serve a purpose being that way?
 

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But apparently don't do it well based on the JT diesels bottoming out on bird poop.
Would be interesting to know how they changed the springs to handle the weight............. and the shocks as well to match.

The thing with this situation - I have nothing to compare to as far as a frame of reference - if this truck had the same springs as the 2020 I'd know how much change there would be with the lighter Rubicon springs.
But I have to assume this truck is heavier as the payload number is a lot lower than the last one.
So I'm assuming the Rubicon springs I have would yield less than the 1" I got with them under the other truck. But that's a guess or assumption.

The Synergy springs are looking pretty good so far - I may contact them with a couple of questions.

I was going to do as suggested and install the winch and bumper and see how far things settle to help decide on which spring, and other factors, but I decided to powder coat the steel bumper Problem, I'm tied up with customer stuff - and the main bumper part is too big for my oven or my sandblaster so I had to hire that done - 2 weeks. Ugh, that's cutting things close for upcoming trips, my doctor/test appointments and so on.
You will have the upgraded bump stops from the factory. Also and importantly, I believe the jounce bumper tower is longer on the diesel to prevent upward travel and hitting components on the diesel motor.. If you shouldn’t have this. I’ll try to measure this weekend.
 
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Why do you say the Rubicon had lighter springs? I've never heard this or read into it. Do they serve a purpose being that way?
I said: " My 2020 had the lighter number Rubicon front springs under it. "

There are at least 3 different Rubicon front springs - possibly more. My truck had the lighter of those springs, the lightest Rubicon front springs I had seen.
Not all Rubicon springs are the same, I meant I had the lighter number of the Rubicon springs - I left out a word..........

Overland has light springs, possibly among the lightest of all JT springs. They are also longer than any other JT spring (that I have seen). They are longer than Mojave springs, and a good 1"+ longer than the light Rubicon springs. The Overland springs are only a few digits away from the light Rubicon spring.
Example - Overland 330, Rubicon 340.

2020 Overland Springs-
Left front - 325
Right front - 330
Left rear - 439
Right rear - 440

My set of Rubicon springs (the lighter set of Rubicon springs)
Left front - 339
Right front - 340
Left rear - 449
Right rear - 450

You will have the upgraded bump stops from the factory. Also and importantly, I believe the jounce bumper tower is longer on the diesel to prevent upward travel and hitting components on the diesel motor.. If you shouldn’t have this. I’ll try to measure this weekend.
I have the gas Overland. Should be the same across all years of Overland with the 3.6
I find it odd that Synergy generically says 2" bump stop needed.
I can only see 2 reasons to extend a bump stop -
prevent the shock from bottoming out and possibly damaging the shock
or
Prevent the spring from fully collapsing.
Or perhaps it's to prevent you from coming down on larger tires? I am not going to be running any huge tires.......... when these tires go I may up to 33" but no more on stock 3.73 gears.

If you have not changed the shocks, then sitting 1" higher is going to ensure your shocks aren't going to bottom out. If they didn't bottom out before - lifting it will not cause the shocks to bottom, it would for sure prevent it.
So that leaves preventing full spring compression - setting the spring, coils full compression.
That's the only reason I'd see for extending the bump stop.
 

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4 reasons for bump stops.

1. To keep the shock from bottoming out.
2. To keep the axle from hitting the engine.
3. To keep the tire from rubbing on full compression.
4. To keep the coil spring from coil binding.
 
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4 reasons for bump stops.

1. To keep the shock from bottoming out.
2. To keep the axle from hitting the engine.
3. To keep the tire from rubbing on full compression.
4. To keep the coil spring from coil binding.
I would expect 1, 3 and/or 4 would prevent 2 from ever happening. (unless your springs have only 3 or 4 coils, your shocks can compress to 12" and you are running 26" tires)

My concern now is shock length - and busting shocks - there's no specs on comparing shocks like the stock Overland shocks to Rubicon shocks, or the latest Rubicon diesel shocks so I guess I'm on my own comparing the stock shocks to the Rubicon shocks I have but I'd rather know before it's torn apart so I can prepare with any other parts I'll need.
It's been suggested that the shocks mentioned in the TSB fix for JTRD clunking on bumps would be valved well for the springs I've mentioned. I guess I worry about length when I see what the final results are after installing the winch and bumper - see where things settle out.
 
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2022 Overland. Will be putting my steel bumper, skid plate and winch back on. (had them on my 2020)
That will add about 150 pounds to the front.
My 2020 had the lighter number Rubicon front springs under it.
Left front - 339
Right front - 340
Those gained about 1" up front when the truck was otherwise stock.
When I put the winch and bumper on, it dropped about .5"
I then added Daystar 3/4" spacers to bring it back up for a net gain of roughly 1.25"

The 2022 Overland has very different spring numbers under it - so if the current Overland springs are stiffer, that means these light Rubicon springs won't gain me as much. There's no way I know of to compare the 2022 front springs to the 2020 front springs.

Another twist in the road - I'm likely to get a snow blade for the JT this fall...............

I want to:
  • Keep the ride this truck has as much as possible
  • Add the bumper, winch and skid plate
  • Have a net gain in height of roughly 1.25" on the truck after the bumper/winch, etc. are added.
  • Have the truck not drop to the ground with a blade on it for winter.

I'm just thinking that the current light numbered Rubicon springs aren't going to do it.
No way I can go with 2" or higher lift - not with my wife already complaining getting in and out with bad knees and such. Almost every "lift" is advertised as at least 2" and we know that it ends up being over 2" if you read all the posts from people that use a so-called 2" lift on anything except Rubicon.
Going over about 1.5" means more parts, centering the axle, making up for caster loss and so on.
PLUS - the expense involved of a lift is just not possible. I went the Rubicon spring and Daystar spacer route because it was a mere fraction of any other way - and frankly, the Rubicon springs really didn't change the way the front of the truck handled rough roads.

So looking for ideas, maybe things I have not considered (very possible) and doable for under 400 bucks or so (I don't have that much in the spacers and these lighter Rubicon springs) 300 would be closer.
If you have the 3.5L engine. One possibility is look at getting a set of the Diesel engine springs and shocks. They are rated for the heavier engine and should be a bolt on option.
 
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Right front Synergy spring and right front Rubicon spring -

Jeep Gladiator Trying to think through front spring options 20220823_105608_HDR


Right front Overland spring (top in pic below) and right front Rubicon spring (bottom in pic below)

Jeep Gladiator Trying to think through front spring options 20220629_144638
 
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I'm in the process of putting steel bumper and winch on. So far the stock springs have settled 3/8" and I don't have a skid plate mounted, and the ends aren't yet on the bumper.
Interesting that the Rubicon springs I had under my 2020 dropped 1/2" when I put the steel and winch on the front, and looks like the Overland springs will end up dropping 1/2" in the end, too.
Measuring every so often to see how things end up.
 

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Right front Synergy spring and right front Rubicon spring -

Jeep Gladiator Trying to think through front spring options 20220629_144638


Right front Overland spring (top in pic below) and right front Rubicon spring (bottom in pic below)

Jeep Gladiator Trying to think through front spring options 20220629_144638
It is so strange to me still that the rubicon springs are so much shorter... Just seems, wrong.

Anyway looks like you made a decision? But did you give any consideration to AEV? I know you have body issues - I can totally relate!!! AEV I think is right at that 2" mark, and my Rubicon currently barely lets me get in without tippy toes. Anyway, AEV (and Robinson) have their front springs rated for an additional 150 pounds of bumper/winch. But I believe the rate is the same as the Rubi. So it would still drop a tad with a plow but I would think otherwise it would be perfect for your setup. Rear springs I believe have 3 options - factory weight (unloaded), +450 pounds, +750 pounds. Personally I am going to go the +450 pound version likely. They are also very simple with brackets using the standard control arms - although adjustable track bars would be beneficial.

Just throwing it out there since I didn't see it discussed before? I would be curious if you did not want to go that rout why it would be. Hope you find the right setup!! At least there are plenty of options to choose from these days!!
 

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Right front Synergy spring and right front Rubicon spring -

Jeep Gladiator Trying to think through front spring options 20220629_144638


Right front Overland spring (top in pic below) and right front Rubicon spring (bottom in pic below)

Jeep Gladiator Trying to think through front spring options 20220629_144638
How did your truck turn out? Very interested to see the final look and measurements achieved. I have an Overland and was looking at either Synergy or Eibach 1” lift springs. Eibach I would have to use Wrangler front 1” springs though.
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