Backend Bottoms out easily...

jscherb

Expedition Leader
While it is true the bags provide some load support by exerting pressure on the could, they can also slide up and down. If the bag is too short, then you actually can unintentionally create a multirate spring...and cause a bad/unexpected bounce when the bag is finally compressed : source - Airlift. Experienced the slide and bounce first hand.

Reason I know this - my original set from airlift had the wrong bags ( too short) included. I called and spoke to their PM about the issues I was having...so in short, I would need the longer bag if I opt to go that route...

sent via the cone of silence
That differs from my experience. In both of my LJs, there are several inches above and below the air bags inside the springs - in other words the bags are shorter than the springs. These are the factory springs and the recommended Air Lift kit for the factory springs and the bags are shorter than the springs. By keeping them at no less than the recommended minimum pressure, they don't move. But if you decide on air bags you should take whatever advice you get from the company.
 

kojackJKU

Autism Family Travellers!
mine filled the space in my spring....weird. I had like 1 inch on bottom before the bag hit the mount. then it was all filled. They worked great and gave my rig a great ride.
 

Stryder106

Explorer
mine filled the space in my spring....weird. I had like 1 inch on bottom before the bag hit the mount. then it was all filled. They worked great and gave my rig a great ride.
This is how my Air Lift bags were. When pressured up - they filled the springs top to bottom and bulged between the coils.
 

jscherb

Expedition Leader
This is how my Air Lift bags were. When pressured up - they filled the springs top to bottom and bulged between the coils.
Must be that the JK version of the air bags is longer and fills the springs and the TJ/LJ version is shorter and doesn't fill the springs top to bottom.
 

vtsoundman

OverAnalyzer
That differs from my experience. In both of my LJs, there are several inches above and below the air bags inside the springs - in other words the bags are shorter than the springs. These are the factory springs and the recommended Air Lift kit for the factory springs and the bags are shorter than the springs. By keeping them at no less than the recommended minimum pressure, they don't move. But if you decide on air bags you should take whatever advice you get from the company.
Understood and agreed. First set of bags Airlift sent out were for the wrong application... literally the wrong part shoved in the right box. Too short...may have been the wrong diameter too. Kept min pressure of about 7-10 pain all the time.

mine filled the space in my spring....weird. I had like 1 inch on bottom before the bag hit the mount. then it was all filled. They worked great and gave my rig a great ride.
That is how the replacements were...about an inch shorter and fit tighter.

Ya know, it could have been multiple issues that drove me to think the airbags were the problem...with both you guys liking them. When I swapped all the CAs with new takoffs, two rear bushing were shot, some failed Ranchos and tired OEM springs. I've done multiple cross country trips rolling heavy and tow all the time. On one trip (before airbags), I moved several hundred bottles of wine, a good portion of my tools, and my/wife's wardrobe. Thought we were a little heavy. Imagine my surprise when we rolled across those scales in the middle of nowhere Wyoming...We were about 1000#  over GVWR on that trip...

sent via the cone of silence
 

rubicon91

Explorer
Had a similar problem with with my TJ after having an ARB tire carrier and a heavier spare tire mounted. It nailed the bumpstops every time I hit a significant dip on the road.

I initially had the heavy duty OME springs with no problem but they were on for a long time and were worn.

Thinking my springs were simply old and shot, but not entirey sure that i should just replace with just a new version of the same.

So I emailed ARB my situation and a rep then responded back after a day or two, and he provided me with three different coil spring options recommendations and their corresponding part numbers.

I couldn't be happier with the new springs and all things considered, ARB's support, and they were not that expensive at the end of the day.

You probably would be best served getting your shocks reworked as the Fox guy suggested, along with some heavier duty rear springs.

Good luck!

Sent from my SAMSUNG-SM-G891A using Tapatalk
That was my comment back on post #11 for you vtsoundman. At this moment I could not be happier wiht just getting better coil springs for the rear. The stock springs had me losing 2.5 inches of height when i just had the stuff of my old JK added to my new one. When I added the new coils I gained back the height in the rear and it now sits and rides perfect again with all the added weight. Cheap solution to see first and foremost and simple to install. I think I spent about $150 or so with northridge and the discount code. Might want to give that a shot with some stronger coil springs.
 

vtsoundman

OverAnalyzer
That was my comment back on post #11 for you vtsoundman. At this moment I could not be happier wiht just getting better coil springs for the rear. The stock springs had me losing 2.5 inches of height when i just had the stuff of my old JK added to my new one. When I added the new coils I gained back the height in the rear and it now sits and rides perfect again with all the added weight. Cheap solution to see first and foremost and simple to install. I think I spent about $150 or so with northridge and the discount code. Might want to give that a shot with some stronger coil springs.
I did see that - and appreciate the perspective on the RK springs. I like the idea of a multi-rate coil....but people rave about the linear OME coils too.

Did you ever weigh your rig and get an idea as to the difference in loaded vs unloaded weights?

Someone asked for some photos of the bumpstop..and current suspension.

Jeep as it sits now...about 100# in the back. Rest empty except extra batt that is perm mounted in mid section. Stance is fine
IMG_20170630_085846 (Large).jpg

Sumospring Progressive Bumpstop & Mopar spacer config...Note: the Sumospring is only 3/4" or so longer than the OEM snubber/bumper.
IMG_20170630_085928 (Large).jpg

Image showing amount of shock travel left...the piece of flex loom was part of the airlift tubing I had installed - must have fallen /broken. I'll need to remove that when I get home.
IMG_20170630_090011 (Large).jpg


Pic of my lil jeep trailer...
IMG_20170630_085855 (Large).jpg
 

rubicon91

Explorer
I did see that - and appreciate the perspective on the RK springs. I like the idea of a multi-rate coil....but people rave about the linear OME coils too.

Did you ever weigh your rig and get an idea as to the difference in loaded vs unloaded weights?

Someone asked for some photos of the bumpstop..and current suspension.

Jeep as it sits now...about 100# in the back. Rest empty except extra batt that is perm mounted in mid section.
View attachment 407615

Sumospring Progressive Bumpstop & Mopar spacer config...Note: the Sumospring is only 3/4" or so longer than the OEM snubber/bumper.
View attachment 407614

Image showing amount of shock travel left...the piece of flex loom was part of the airlift tubing I had installed - must have fallen /broken. I'll need to remove that when I get home.
View attachment 407613


Pic of my lil jeep trailer...
View attachment 407612
I didnt get it weighed before I added everything but it was some significant weight I added in the rear. I wrote it down at the time to see and I want to say it was 200 lbs approx over what I took off that was stock. The 1st picture here below is what it looked like right after I added the coils on to it. The second pic is about the only picture I can find that has everything in there and is loaded down to remotely show the sag. It was profound when looking at the Jeep. I added a LOD rear bumper/tire carrier, Gobi stealth Rack, Arb 50qt fridge on slide, Goose gear floor plate. All this was what I stripped off my 2012 Jeep to put in the new one. The last pic I was about to head out for a trip and was fully loaded down with the trailer. It rode perfectly and towed like a dream on that trip. Hope this helps some. When I called Northridge to discuss everything with them I was looking at the 2.5 coils and they said no way as that would raise me way high in the rear and that the 1.5 would work best. So after much consideration I decided to see and glad I did.
 

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vtsoundman

OverAnalyzer
Just finished doing some quick experiments with adding weight to the back (measuring deflection) on my Jeep and neighbor's stocker, ... suggests the spring rate is identical to stock or slightly softer on the Mopar 2" lift spring.

Mine dropped ~3/8" more than her JKU Sahara at the perches. Yeah I know I need a machine to determine rate and lots of other things can impact settling..

But a static load test is good enough at this point.

I am going to try new springs first then a set of shocks...looks like i have 3 options : OME, Ynergy and RK.

Shocks: I don't have any of my older takeoff shocks left (Monroe, Rancho, Stock Rubi) to compare the bottoming out of the Fox's...but noticed the body roll with any weight is pretty significant. Completely empty (including remove extra battery, no gear in cubbies, etc) it rides awesome - smooth, limited body roll, some extra tail end dip, but not bad, etc...and off road it's pretty decent too.


sent via the cone of silence
 
do you know the free and collapsed length of your springs? I run a 187# spring in the back of my 05 LJRU and love them, I'm loaded down and almost no coil sag. they are 9" at ride height and 14" free, gives me around 3" of lift, that should give you around 2". ps. I have a 30gl gas tank,roof rack, awning,spare tire {315/75/16}and a Oz tent on the jeep.
 

vtsoundman

OverAnalyzer
HI Folks - Thought I would update this thread. Well, we went a bit of a different direction since I posted this thread. We bought a 4x Sprinter Low Roof 144 and put on a 2" lift with 35s, a poptop, and some other goodies...and this has been our primary overlanding vehicle. The Jeep will be used as a solo trip & fun trails vehicles.

We opted to slow/stop any further after market purchases on the jeep and it has been somewhat ignored. The jeep has been somewhat ignored since we purchased the van...but not as much anymore.

The bottoming out has continued but the passenger rear seems to hit harder than the driver rear. The passenger rear has also an increased rear sag... I checked the spring part numbers and they are correct. I measured the height from stock (using the rear bump stop and front shock length). My front resulted

I have since installed an AEV full width bumper, a 9k Warn Synth winch, a group 31 100aH battery under the hood (using a JSS battery tray), a 2nd 100ah battery in the back (under a platform that replaced the 40 portion of the rear seat, driver side). ACE rock rails were also installed. The rear remains stock (save a custom Harbor Freight interior cargo rack). Based on the above spring values, I can only conclude that I am under sprung - the front of the jeep has less than a 2" lift over stock. Other Jeepers on other forums have indicated they've seen >2" (most 2.5 - 3") at the front axle with a full width steel bumper and winch.

Looking at old pics (right after the lift was installed) to just before I installed the bumper & rails, it appears that my Jeep's springs had sagged quite a bit before the above parts were installed. However, I didn't measure any of it.

Overall, I have about 40k miles since the lift was installed and less than 7k since the bumper, winch, and rails were installed. Most of my trips have been with the Jeep above GVWR by a few hundred pounds... (say 50-60% of the miles).

My measurements as of 5 min ago with (less than 1/2 tank)
~20.25" in the front (1.75" above stock)
~7.25" in the rear. (~roughly 2" above stock)





I'd like to run towards 37" tires, flat fenders, and a 3.5" lift. Knowing that is a ways off, I'm going to try some scratch & dent Metalcloak 2.5" springs. Metalcloak's philosophy is 'stiff spring/soft shock' - since the Fox Mopar shocks are known to be soft, I am going to give this combo a try for a bit. The Mopar Fox shocks are short and I have plenty of uptravel with current spring/bumpstop setup - if Iike the spring shock combo, I'll throw on a set of shock extension brackets and run this setup for a while.

My next heavy weight mod for the jeep is a full steel width bumper and full aluminum skid plates. I'll install the Teraflex tire carrier and Titan Fuel Aux Tank.

What do folks think?
 

vtsoundman

OverAnalyzer
So my source for Metalcloak springs turned out to be a no-go. Anyone running RockKrawler Springs on their heavier expo'd jeeps? What do you think of them?
 
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