So what you are saying is the FOR coils does all these things? Work on a loaded or unloaded truck, keep the same height, irrespective of load and the truck stays level doesn't matter what application?
Before I answer, let's be clear. I do not have a horse in this race. What I am telling you is to buy the Slee springs, not to change your mind and get a F.O.R. suspension. I have never run Slee's springs, I have never ridden a truck with Slee's springs, and I have never criticized them. I am talking about OME, and I am doing that by comparing to the other suspension I have run, which is F.O.R.
On to the response:
Nope, what I am saying is they do this far better than OME coils. I'll go on a statement I see on this thread as an example: "OME J springs will give you 3.5" in the rear fully loaded, and 5" unloaded". I have certainly seen plenty of threads that lead me to believe this is true including pictures of incredible stinkbug, and lots of people have commented on how crappy it rides unloaded (harsh).
Now, an OME J rear coil is 250/lb inch spring rate, which as we know means it takes 250 lbs to compress the spring one inch. That's 500 lbs of weight to compress the rear end one inch, and 750 lbs to compress the 1.5" that makes up the loaded vs. unloaded spec on OME J springs.
750 lbs just on the rear suspension is an enormous amount of static weight, and would take up a major percentage of the vehicle cargo rating. I have no idea how you get 750 lbs out of a rear bumper, tire carrier, spare, tire, hi-lift and some spares and tools leveraged entirely over the rear suspension.
What this means is that a level riding 3.5" J spring is compressing 1.5" with far less weight than the spring rate would require, and to me that means the spring is not maintaining its rate as you load it.
Now when we hear a lot of people saying that the unloaded stiff and harsh riding J spring at 5" of lift becomes wallowing and unstable on a "heavy rig", my statement that the spring is losing load bearing capacity as load increases makes sense. If the spring is designed for so much weight that unloaded it would provide 1.5" increased static ride height, then why is that same spring having difficulty handling that height when properly loaded?
This issue is encountered across all of the moderate rate OME springs.
Like I said, you can tinker with different OME coils, etc., but I do not believe you will ever get adequate load bearing across a full range of usage with an OME coil without suffering major ride quality and suspension height variances. You can pick a set of springs and keep load relatively constant and whether you like it or not is purely preference, but a big point of the 80 is big load variances for a range of multi-purpose uses, so I want a coil that can handle big load variances without radically changing its characteristics.
Now we can go back to F.O.R. Gen I to illustrate that coil design matters (which again is why you should buy Slee coils over OME for use with OME L shocks). That kit was 227 lb/in front and ~254 lb/in rear stated spring rate, which means approximately a J spring rate. It used incredibly soft shocks, Bilstein 4" TJ lift shocks to be exact with a slightly stiffer custom rear spring rate, but basically a 168/73 valving. Hence the bounce on load or big dips, as NorCalSam would testify.
But let's look at just the springs. I took these pics just to show load bearing of F.O.R. coils because of the years of posts about "what OME springs should I get to ride level" and the responses of "just add 500 lbs to the rear so it rides nice".
In the first pic, I am completely unloaded. Just the 3 rows of seats. No tools, spares, or anything else. The vehicle is completely level hub to flare on all four corners (23" hub to flare with no flares).
In the second pic (which I actually took first), I am towing a 2,000 lb 12' open U-haul trailer with six cubic yards of damp mulch. Conservatively, 3,500 lbs. I also have my high lift, tools, spares behind the 3rd row, plus about 125 lbs of 3 kids in the 3rd row. The trailer was evenly loaded, so 10% tongue weight hanging off the hitch (350 lbs) plus 250 lbs more of kids and gear either over or behind the rear suspension. In other words, a 600 lb difference leveraged on average well behind the 3rd row.
I jounced the suspension between loaded and unloaded to ensure the measurements were good.
The loaded to unloaded rear measurement is 3/4" of compression for 600 lbs. The OME J spring under this kind of load is doubling that compression with the same stated spring rate to get to a 3.5" loaded state. This means the effective load bearing across a 600 lb load range for the F.O.R. coils is dramatically more consistent and higher than the OME coil.
If you want to see the radical variance in OME J lift heights, read this thread and look at the pictures. Brett goes unloaded and gets a 6" lift where others have 3.5" on the same springs, has to add a big front spacer, and ends up with all of the big lift complications you are avoiding by not buying a big lift. I go unloaded and stay at my 3" lift, fully loaded 3/4" compression where the lines of the rig still look level because the 80 design has a rake to the rear visually. Which springs would you rather have? Buy the Slee 4" springs, not OME.
https://forum.ih8mud.com/80-series-tech/258740-ome-j-lift-install.html
