After getting very frustrated trying to find reliable information on OME leaf springs while researching my own purchase, I feel an obligation to add what info I have for future searchers. It's definitely best to always use part numbers for OME springs, because currently there are no less than three "medium load" leaf springs in the ARB catalog.
I found this list fairly helpful:
OLD MAN EMU-CS034RA (OMEJC1A) 5 leaves in pack, 148lbs/inch s.r. 230mm (9.055") free height= Average lift of ~3"
OLD MAN EMU-CS034RB (OMEJC1B) 5 leaves in pack, 148lbs/inch s.r. 205mm (8.07") free height
OLD MAN EMU-CS035RA (OMEJC2A) 4 + 1 overload, 137/257lbs/in s.r. 235mm (9.25") free height
OLD MAN EMU-CS035RB (OMEJC2B) 4 + 1 overload, 137/257lbs/in s.r. 210mm (8.27") free height
OLD MAN EMU- D22XL (OME Add A Leaf) ~ 1" lift on top of their lift packs
But unfortunately it's outdated. When I called ARB, the person I spoke with was extremely helpful because he informed me that they were re-introducing a couple leaf spring part numbers that had been discontinued for a few years. Here are the current leaf springs in the catalog:
Code:
CS034RB Light Load 2.0"
CS034RA Medium Load 2.25"
CS033RB Medium Load 2.75"
CS033RA Medium Load 3.5"
CS035RA Heavy Constant Load 2.0"
The "A" or "B" denotes taller or shorter free heights, respectively. The "034" leaves are 5 leaf packs. The "033" leaves are 5 regular + 1 overload leaf packs. The "035" leaves are 4 regular + 1 overload leaf packs. From photos I've seen of CS035RA, the overload leaf is fairly flat, or curved down slightly, which leads many to fear catching them on rocks or branches. The overload leaf on CS033RB is curved upwards and seems to fit quite nicely with the rest of the pack. I can't imagine having much of a problem catching it on things.
Clearly ARB considers a "medium load" to be quite a lot of weight. I saw reports of CS034RA giving anywhere from 3" to 4" of lift. I saw reports of CS035RA giving a similar 3" to 3.5" of lift.
I ended up purchasing CS033RB, which I feel was perfect for my application. I don't do any rock crawling, but I do a lot of camping trips down rough roads with a very heavy load of camping gear. The overload leaf means that I would worry about folding the XJ in half before I'd overload the leaf springs. I also find I love the ride both loaded and unloaded, when paired with Bilstein 5100 shocks.
The CS033RB springs ended up giving me just shy of 4" lift in the back (unloaded), even with a Detours Slimline rear bumper and a 31" spare on the carrier. Clearly more than the 2.75" they list in the catalog. This is after a year or so and several camping trips.
Hopefully someone finds at least some of that helpful. I know I would have. :cheers: