Which shocks and coils for my LJ?

[Roktoys84]

I'm getting very tired of my rough riding Unlimited. It's currently set up with a custom Mt. Logan Offroad long arm lift with 6" Fabtech coils and Skyjacker shocks. It has bumpers, sliders, corner guards, and a 37" Cooper hanging on the tire carrier. It bottoms out the rear suspension very easily off road even unloaded, I don't even have the rear seat in. I'm looking for more load capacity for times when I'm carrying my Engel and I would like to add some fuel cans to my tire carrier soon. What is the general consensus on coils and shocks? I was thinking of Bilstein 5100s but don't know where to start for coils.

 

[kjp98TJ]

currie, RE, or procomp springs tend to be on the "stiff side". i've had 4" PC coils for 4 years and i don't think i've losta 1/2 inch. get a nice complimentary shock

 

[ntsqd]

Are you seeing higher speed bottom-outs or low speed bottom-outs?

The 5100's will work nicely for the lower speed applications (4-40 roads etc.), but if you're occasionally playing Paranelli Jones then you may need to look for something with a remote reservoir to get the additional cooling they offer.

No one spring is going to ride smooth both loaded and unloaded unless it has an adjustable spring rate. If unloaded driving is a significant portion of the annual mileage I would look for a spring that rides nice unloaded, and then install air springs to handle the additional weight of being loaded.

 

[Roktoys84]

Are you seeing higher speed bottom-outs or low speed bottom-outs?

The 5100's will work nicely for the lower speed applications (4-40 roads etc.), but if you're occasionally playing Paranelli Jones then you may need to look for something with a remote reservoir to get the additional cooling they offer.

No one spring is going to ride smooth both loaded and unloaded unless it has an adjustable spring rate. If unloaded driving is a significant portion of the annual mileage I would look for a spring that rides nice unloaded, and then install air springs to handle the additional weight of being loaded.

It bottoms out at medium speeds, around 15mph. The Jeep was built with crawling in mind and it work great for that, but on backcountry roads it gets uncomfortable. It seems silly now that I was trying to cut costs on a $30k Jeep but we thought that the Skyjackers would be "good enough." I'm planning on replacing the shocks first and the springs later. Do you have a link for the air springs?

 

[Steve Curren]

People have used Air Lift and are happy, I went with a product from JKS named ACOS. I had an 2005 LJ and had problems when coming off an obstacle the rear would bottom out also when pulling my trailer the ACOS would help to level the load.

 

[Roktoys84]

It looks like Air Lift leveling bags and new shocks might be the ticket. Will the air bags work with 6" coils? Does anyone think that Bilstein 5150s will give me the ride I'm looking for? Any other shocks I should look at?

 

[goodtimes]

I have had the Fox 2.0 remote reservoir shocks on the front of my TJ for a couple years (don't recall what the valving is set at)....quite happy with them, but if I were to do it again, I would spend the $$$ for the adjustable low speed damping circuit. I'll eventually use the same shocks in the rear.

 

[nwoods]

I have RE 4.5 springs in the rear, Currie 4.5" springs up front, and Rancho 9000 shocks at all four corners running 35" tires.

My rig works pretty well on the street and in the rocks, but I bottom out in the rear at slow off road speeds also. Was thinking about going with RE 5.5" springs in the rear to address that, but not sure....also been thinking about going with all OME (shocks and springs), but can't seem to get specific figures for total amount of lift provided by their HD set up.

 

[Roktoys84]

My Jeep rides pretty rough on the street but I blame part of that on the Rubicon Express Super-Flex joints. They don't ride as smooth as rubber bushings. Anyone have a part number for the Air Lift bags that will work with 6" coils?

 

[monele]

Talked to a lot of folks about shocks before choosing them for my LJ. Skipped over skyjacker since 8 different people said I would hate the ride (way to firm for a jeep, they are valved for a 1/2T truck) I was also told that the 5150's are pretty firm. I agree with the Rancho 9000 suggested above, I think adjustable shocks are the way to go (I have Procomp MX6, but replaced their crappy bushings and added Bar-pin eliminators from JKS on the rear, as procomp bushings tend to fall out) They ride great and I can set them based on my load (I run 2 notches up from the softest setting) I also replaced my Bump-stops with Timbren progressive rate rubber springs so that the high speed whoops in the desert don't make the rear end hit so hard. They are comparable to adding shock bumps to the shock or air bumps above the axle but are WAY cheaper. (the only trick is getting extended bolts so they work with a lift) So far I am VERY happy with this set up. (Jeep is lifted 3" BTW)

 

[86cj]

I have been through this problem with my LJ. I run BDS 3" springs and 5100 Bilsteins, the fronts are perfect. I would be interested the 4" progressive rear coils from Currie but they are to tall for me. I also wonder how the 3" Nth progressive springs would work for me. I went for the Air lift bags and it cured the constant bottoming completely. I am very happy with high speed and low speed performance,I have ran them for 3 seasons and have no issues at all. I have had Air lift or Firestone air bags on 5 different Vehicles some for 15 years and only had to fix one air line that was 10 years old. It would seem the bumpstop is trying to pop the Bag but not yet anyway, and the almighty Flex seems fine. The timbren bumpstops seem like a easy way to add some improvement, the air bags require spring removal to drill the hole in the spring seat for air line.

I can recommend the Bilstein 5100's, I had hydro shocks installed and the Bilstein's made the Jeep way more stable and comfortable. Shane at Bilstein steered me away from the generic 5150's..

 

[nwoods]

What do you use to control the air lift bags?

 

[86cj]

I do have onboard air, but I set them for the condition manually and prefer to run individual lines to an easy to reach close location. I like to be able to have each bag at its own pressure for uneven weight or wheelhop issues.
I run between 10 and 25 PSI (usually 10 to 15 PSI), the bags lose a pound or more just checking the pressure so volume is small. For off road it should give better flex if you use the tee fitting that comes in the kit. Air should bleed over to the other side when axle articulates, (in theory) I don't know if the lines move air quick enough or not....


I have decided to try some timbrens on the front before I go to the Dunes next summer. If the rear air bags don't survive the whoops at the bottom of test hill I will let you know......

 

[ntsqd]

It looks like Air Lift leveling bags and new shocks might be the ticket. Will the air bags work with 6" coils? Does anyone think that Bilstein 5150s will give me the ride I'm looking for? Any other shocks I should look at?

No idea on the air assist springs. Suggest looking at applications like El Caminos and various full sized station wagons. I know both Ford & GM full size wagons are coils in the rear from the late 60's. No idea about Chrysler/Dodge's.

As far as I know all of the 51XX series Bils come valved the same, 255/70. That works well with leaf springs, but can be soft for coil springs. Their std valving for coils is 360/80.
I would look to see if there is a part number with the 360/80 valving, or if there is a specific p/n for your chassis and lift combo. Even if the valving for a specific combo isn't listed I would expect Bilstein to have arrived at a good set of valving specs.
I will say that I took Ranchos off of Patch to install Bilsteins, and I haven't looked back. I am in-process of doing the same, only with 2" Fox's on the FJ60.

It strikes me that the Rancho 9k shock control system could possibly be used to set air spring pressures from in the cab and still keep them separate.

 

[Roktoys84]

I finally pulled the trigger on some Bilstein 5100s and got them installed Saturday. Huge difference. The Jeep feels alot more firm now, but rides much smoother on rough roads. I also figured out the sagging problem. Once I actually pulled off a tire and climbed underneath it was pretty obvious, my coil had slid off the 1" coil spacer and crushed it. So I ordered new 1.75" Daystar spacers and I'll install the Air Lift 1000 kit at the same time. I'll report back when I get the air bags installed but I expect them to make the Jeep work much better when it's loaded down.