Thanks for the help Pirate!

If I was going to use your suggested kit, what would it all entail? I’ve looked over some older threads and found some shopping lists.

procomp 22210/22415
PMF 5/8” u bolts (9.5” length?)
PMF braided steel brake lines
PMF top plates (for replacing bump stops/snubbers)
WFO 2* shims x4
Bilstein 5100 x4 or Fox 2.0 remote resi x4

I was also thinking of replacing the shackles front and rear as they are likely worn. Any brands you would suggest?

Anything else you would add or that I am missing?

Kobra

 

front shackle bushing

Dorman 722-025

rear shackle

Dorman Products 722-018 Leaf Spring Shackle

 

So I’ve been diving into leaf spring technology and setup to try to understand it better before buying anything.

I stumbled across a few articles and videos about shackle angle and how important it is to good ride quality and suspension travel.

It seems leaf springs end up losing a lot of travel when people lift their vehicle and change the shackle angle. The closer to 90* the shackle gets when at ride height/compressed, the lower amount of travel the spring has and the higher the effective spring rate becomes.

From what I’ve learned, shackle angle around 45* offers the most up travel and down travel on a leaf spring, but also reduces the leaf springs effective spring rate, which means the spring becomes “bouncier”, meaning shock tuning becomes very important.

I’m having trouble applying what I learned to the Excursion’s suspension though, any help @pirate4x4_camo ?

 

Unfortunately much of what you read on the internet about shackles is Bro Science.

lifting and losing angle
depends on how you lift the vehicle.
use a longer spring and keep the factory shackle angle

Effective spring rate.
shackle angle does not effect spring rate or cause more bounce.

shock tuning is always important.

Applying to your Excursion.
unless you are having a spring built to your specs you don’t really need to worry about shackle angle.

 

Interesting.

I’ve copied two links for you to check. You know more about suspension then I do, so you may be able to check these out and see if there’s any validity.

https://www.pirate4x4.com/threads/le...metry.2283090/

 

Fwiw, i am the owner of pirate4x4

the discussion has plenty of merit but these guys are engineering suspensions from scratch to do things your Excursion could never do offroad.

it is a good discussion if you like to nerd out on suspension theory or are building your own springs. Otherwise slowly back away from the rabbit hole.

The guys in that thread are building these.

 

LOL. I figured when I saw Pirate4x4 that it couldn’t be a coincidence…

I love to nerd out on stuff like this… learning why things work, how they work etc. is fun to me… my wife on the other hand doesn’t enjoy it when I go down a rabbit hole for weeks at a time! Lol.

I’ll *try* to ignore what I’ve been reading and back away slowly 😂

Thanks again for the help.

As far as suspension for the X goes I’m either set on going with the ProComp springs, Carli/Deaver springs, or going all out on Full Traction 4-link conversion.

The price difference between Carli setup and Full traction isn’t much, which has me trying to determine if it’s worth it to stay with leaf springs or convert to coils.

I may go “cheap” with the ProComp springs and see how I use it/enjoy it. If it breaks or I use it enough to warrant upgrading then I can go that route in the future.

 

Fwiw, i have run all 3 of those at various times over the years, and you really can’t go wrong with any of them but at the end of the day the performance will come down to the shock regardless of who’s leaf or 4 link you use.

currently on my own 4 link front with 2.5” coilovers in front and a procomp spring out back with 2” fox. Shocks are secret squirrel valving

 

Yeah, after reading so many other threads with you explaining suspension physics, I’ve realized shocks+travel are the biggest predictors of ride quality… and shock valving is the key. That’s why I’m going to spend the money once and buy good quality shocks and have them valved for the X.

It really isn’t much different then long range shooting (another hobby I enjoy lol). Spending the money on quality glass (scope) and putting it onto a budget rifle will work out better in the end then buying an expensive rifle and putting crap glass on it.

Buy once, cry once.

Thanks again for your help. I’ll make another thread down the road once I get it all setup.

 

Fwiw,

while i share the sentiment on high end shocks i will say that for street driven rigs the Bilsteins 5100 work great with 37s

the short comings become pretty obvious when you start off roading but for the price they are hard to beat.

 

Alright Camo, last question... hopefully.

I am looking at the ProComp 22210 or 22410 for the front... I need to know whether I am thinking about this the right way.

My front end with the 7.3L weighs 4400lbs (2200lbs per side) and the rear is at 4000lbs (2000lbs per side).

The 22210 are rated at 430 lbs/in, which means they should deflect 5.11" when the weight of the vehicle is on them. I got off the phone with ProComp and the gentleman said he guessed they had around 6" of camber or free arch. That means that these springs will be sitting nearly flat when the weight of the vehicle is sitting on them correct? How will these provide 2-4" of lift that Excursions owners say they do, if they are sitting flat? Unless the only ride height difference is coming from the height of the leaf stack itself...

The 22410 are rated at 435 lbs/in, and should deflect 5.05". The gentleman I spoke to said he didn't have camber measurements on the 22410 either, but guessed they were around 7" of camber, which means they could still have about 2" of "arch" left to them when loaded with the front end vehicle weight, correct?

I want to make sure whatever front spring I choose still has some arch left when loaded with vehicle weight, that way it still has compressible arch (up travel) without going into a negative arch... am I thinking about this the right way?

Edit: Also, I just saw you're located in Northern CA? I'm located in Southern OR, almost on the border to CA. It would be fun to meet up at some 4x4 events and compare X's.
Kobra

 

I see 2 errors in your figures.

1. The front of your excursion at 4400 lbs is the total of sprung and unsprung weight.

since the leafs are not holding up the weight of the axle and tires ( unsprung weight ) you need to subtract that. Axle with tires weighs about 850 lbs,


2. if you want accurate data a salesmans guess is just that. A guess.


Using the ride height method common on this forum hub to fender the stock ex was 23” front 24” rear

the 22210 -22415 will put the 7.3 ex at about 27” to 27.5” And the rear with no block at 27”

 

@Smoothwater did you have to trim fenders? I installed the OME kit on my 2001 excursion limited and the shop said it needed 2" spacers to clear 315/75/R16s. And I still have a fair bit of rubbing on the fender. Something doesn't seem right (but I don't know what it would be though). With the spacers, I have ~2" of tire sticking outside of the fenders. Honestly, I prefer to NOT have that look. I'd rather my tires / wheels be flush with the outer edge of the wheel well / fender more or less.

 

It’s possible that the 2” spacers are what’s giving you the fender rub, have you tried it with the spacers removed? Those 315/75R16s may give you a little bit of spring rub at full steering lock, my 305/70R18s do on OEM ‘04 18” wheels, but I’m only at full lock infrequently and when they do rub there I just back off the steering a touch and they are fine. My Nittos are 35.25X12.8 and they have zero fender rub.
You can also install steering stops to prevent the spring rub at full lock.

 

I was thinking the same thing. No, the shop doing the work called and said they needed spacers in order to stop the rubbing, but I never had a chance to try it out without the spacers first. I think that may be what I do next. I've also noticed that I have a good bit of rake. I am ~29" from center hub to fender in back and more like 26.5" in the front. I am thinking about some approach to level it out up front, which would also create more clearance for the tires. Any recommendations / thoughts on best approach there? Shackle / hanger vs. mini-spring?