Hi all,

First time posting here, but I have been reading up on Excursions for about the last 2 years. Finally pulled the trigger and bought one that I felt confident in and had a great price. 2002 Excursion Limited with 7.3 PSD and 215,000 miles. Currently replacing what needs replaced (MAP, CPS, EBP, ICP, EBV delete pedestal, up-pipes, etc.)

The one thing that this truck really needs is a better suspension. I have been reading a ton on suspension modifications for the Excursion and I have settled on getting the OME kit. My hesitation was not knowing the leaf spring capacities used in the kit. I had contacted ARB multiple times and couldn't get anywhere (the customer service people could only recite the same specs that were on the webpages).

FINALLY, I talked to someone on the international webpage and they steered me to the fitment catalog. I tracked down the leaf spring part numbers (CS018F and CS048R) for the kit and they corresponded to the following specs:

CS018F - 431 lbs/in and 202mm of free camber (7.9 inches)
CS048R - 225/416 lbs/in and 275mm of free camber (10.9 inches) This leaf pack has 5 leaves total, 3+2. So, I assume 3 main leaves and 2 secondary leaves for an average of 340 lbs/in. The multi rate leaf pack adds together instead of averaging. The primary load will likely be compressed into the secondary given the weight of the Excursion’s rear (4000lbs). Which means the spring rate becomes 641 lbs/in throughout the secondary rate’s travel.

Correct me if I am wrong as I am not a guru on suspensions, but what I could find is that leaf spring camber is a vertical measurement from the leaf eyelet to the first main spring at the direct center of the leaf spring (this seems to be what we also call leaf spring travel?) OME also points out in the catalog that the camber measurement is from the top of the eyelet, not the center. So, I believe in order to get a more accurate measurement of travel I would have to remove half an eyelet's worth from the total free camber measurement.

CS018F - front eyelet diameter 51.5mm rear eyelet diameter 41.5mm average diameter 46.5mm
CS048R - front and rear eyelet diameter 40mm

Based on the free camber specs provided by OME, the leaf springs should have the following capacities (based on lbs/in and inches of travel/free camber):

CS018F - 431 lbs/in * (7.9in - 0.915in) = ~3,000 lbs per spring
CS048R - 340 lbs/in * (10.9in - 0.79in) = ~3400 lbs per spring Without knowing when the secondary rate activates, it isn’t possible to accurately guess/calculate the payload rating. I will update if I can find the information from OME/ARB.

Based on these calculations, these OME springs should have plenty of payload capacity (compared to X/modC or V/C codes) and they should offer a very nice off road ride in combination with OME's shocks.

I can't upload the PDF, but it can be found by googling "Old Man Emu International Application Catalog Edition 50" it should be dated Oct 2022.

Edit: Linked catalogue - ARB 4x4 Accessories - Old Man Emu International Application Catalogue | Edition 50 - Page 218-219

What do you all think?
Kobra

Edits: Updated information regarding spring rates for future readers. Updated title to reflect thread changes.

 

Running that lift on mine. Did add the extra D27XL Leaf spring in the back since sometimes I'm loaded heavy.
37" tires with some mild fender cutting. I went with the OME after reading the expitional portal build below.

https://ok4wd.com/old-man-emu-2-25-s...f250-superduty
https://expeditionportal.com/full-si...sion-part-two/

I don't think many run the OME I think it's a great kit and the springs are top notch. Carli is available also if you want to blow some coin.

 

Yeah, I was going to add the extra leaf as well. Should help give the X back the rake it has from factory.

Main reason I posted, was to shed light on the spring capacities as I haven't seen any other thread on any forum that has information about it. Hopefully others with more suspension knowledge can chime in, and hopefully anyone else in the future looking suspension mods for Excursions will see this thread and will know where to go to see OME capacities.

The other option I had read quite often on the forums was to call ATS and talk with Junior about getting X/ModC code springs and Bilstein 5100 shocks. Truth be told, I had already done that and priced out a whole kit with Junior, but was worried about springs and shocks that are too stiff and more oriented for towing/street use then off-road/exploring use.

Some other threads had also discussed the fact the X/modC code swap was an old way of doing it back in the day before new products were available. Since the introduction of new products and more information, it seems going that route isn't the only option to consider nowadays.

Kobra

 

The only difference between the 5100 and 4600 Bilsteins is the length. Stiffness is the same. At least that is what a rep from Bilstein told me.
I went with ATS for my set-up. I was really impressed by Junior advising me not to purchase the front coils (2 WD) from them, but to go with the OEM F-350 type.
One of the best shops for customer service you will find.

 

The leafs “travel” will depend on how far you deflect the spring. Typical setup limits the up travel to a flat position or just a little bit inverted.

flexing most springs past flat drastically decreases their service life due to plastic deformation.

the OME spring rates are the same as stock. 420 lbs inch in the rear and 330 lbs inch front.

spring capacity is measured as travel x rate.

your vehicles ride quality is mostly a function of the shocks as they control the speed at which the suspension can move.

tire pressure, weight, sidewall height and stiffness is also a big determining factor.

 

As far as “better suspension” is concerned you would need to specify what your goals are and how you plan to use the vehicle.

the OME kit use a twin tube shock which is the same design as stock.
they can provide a soft ride but quickly fall short if you work them to hard, Say a dirt road at speed, they are best for small tires on street vehicles.

here is a decent read.
but in general they are just cheap to make and don’t last long.

https://iscsuspension-na.com/resourc...hat-is-better/

just my opinion but a Mono tube is better design for the Excursion.

 

Monotube is better design period!

 

Thanks for the reply @pirate4x4_camo

I was hoping you’d stop by. I’ve seen your comments on a lot of other threads and you seem very knowledgeable about suspension setups.

As far as the OME kit goes. Based on the catalogue that I was told to review by OME, the front springs are stated to have a spring rate of 431 lbs/in and the rear are a multi leaf pack with 2 different rates which I averaged together for 340 lbs/in.

Do you think the multi rate leaf packs are better suited to off road use then something like X/C codes from ATS? Would softer individual springs (but more of them) give a smoother ride/more travel then say an X code spring with only 2 leafs?

I was contemplating the shock selection as well. OME vs. Fox 2.0 Resi shocks vs. Bilstein 5100.

From what I’ve read on some other threads you posted to it seems the stock valving on the shocks will be middle of the road and could be dialed in by a suspension shop by changing the rebound/compression stacks.

Overall, I am wanting to turn the X into a vehicle that can load up my family and go exploring fire roads, forest service roads, national parks, national forests, etc. I don’t plan on running Baja or doing any high speed racing stuff with it.

kobra

 

Ive spent quite a bit of time running forrest roads and wheeling with the OME shock and seems to be fine.

Im going upgrade eventually but haven't had one blow out yet. Id like to hear what the recommendation is for an upgrade if you went to a set of King remotes. I gotta pull off the wheel and tire combo and weigh it.

 

if i can trouble you for some ride height measurements.

if you can measure from the center of the hub straight up to the bottom of the fender lip at all 4 corners. Would be helpful for me to understand the ome setup better.

no need to actually weigh the wheel, just tell me the size gives me an idea of the weight.

as far as recommendations on king, they are what they are. King, Fox, ect. All the rebuildable and tunable race shocks are basically the same, it comes down to finding a tuner you like and use what he services both for parts availability and familiarity. Working with the tuner before you buy the shocks will save you from making expensive mistakes.

 

Here ya go,

Front 28” Rear 29.25”

37” MT Tires &17” Rim

Finding a shock tuner is gonna be hard as I’m in FL.
So I’ll be going through the mail probably.

 

**** note, i misstated the stock rate earlier, they are 380 lbs/in with the 7.3 engine.

430 front is a heavier than I prefer for the front but it seems to be what is mostly available in the aftermarket.

For reference theprocomp front #22210 Is 430 lb/in +4”Rear #22410 430 lb/in +5.5”
On leaf springs you add the 2 rates together not average.

the point of a dual rate in the rear ( like on the trucks ) is to accommodate the lighter truck bed on the primary and lower spring rate pack and then handle a heavy payload when you load the truck bed.

dual rate on the Excursion is pointless at the rates of ome and f250 mod/c because the heavy excursion just compresses the primary down onto the secondary and now you just have to much spring rate, it works and we built these out of junk yard spring packs in the early days because there were no aftermarket springs available, shops still sell the combo because they do not sell enough of them to build a excursion specific spring with the correct rate.

A Bilstein 5100 is a great starting point for you. You will likely not feel the need for more shock from what you have described.

 

thanks,
ya with 37” the Bilstein 5100 starts to really fall short offroad.

i have never worked with these guys but have heard good things
https://accutuneoffroad.com/?gclid=C...BoCjcIQAvD_BwE

 

@pirate4x4_camo

Thanks for the explanation!

So you're saying the OME kit is overkill for the Excursion as the weight will load the primary springs (225 lbs/in) and go straight into the secondary springs (416 lbs/in) for a total of 641 lbs/in?

The thing that attracts me to the OME kit is all the extra work they put into the leaf springs. I could not find whether ProComp does any of this extra stuff to their springs?

Draw tapered and diamond cut
Bolt Clamps and Liners
Fully scragged and load tested
Graphite coating
Military wrap
Anti-friction pads
Flat axle seat area
Shot Peening

Do you know if the ProComp springs have any of this done to them? I tried looking on their website, but could not find anything.

Kobra

 

That isn’t “extra” they are just marketing the basic manufacturing process.

I don’t even know what “scragged” means in terms of manufacturing springs, maybe it’s what some manufacturers call bull ******* or others call dozing, in the end though all leaf springs go through the same basic process.

the friction coat is cool, i have used a product call Slip Plate but like any coating on a wear surface it needs to be reapplied fairly often, not very high on the maintenance list for a daily driver so unless it’s a race car that gets rebuilt after every race it really isn’t something I would bother with.

OME springs are know to be good quality product and I have nothing negative to say about them. Over kill isn’t how I would phrase it, just not the design i would use. if I was wanted a dual rate rear setup I would use a single rate leaf spring for the primary and an air spring secondary because It is adjustable to each payload.