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It hasn't been just wander. It was partially wander and partially nearly losing control going over bumps. That is a combination of bad shocks and wander. My desire to go to different springs is to increase the ability to safely tow. I was basing my statements from this (from SD Truck Springs):
Ford Excursions were built based on the Ford F250 however, they put lighter springs on them to increase ride comfort and have them drive more like a car or SUV then a truck. This becomes an issue for drivers who purchased the Excursion for towing purposes and need a heavier weight capacity. Ford Excursion springs have around a 1980lb capacity per side in the front and 2275lb capacity per side in the rear, the F250 springs on the other hand will give you between 2030lbs and 2630lbs per side in the front and 3000lbs per side for the rear, this is a substantial upgrade. When researching Ford Leaf Springs you will see a lot of information about spring codes. The most common switch for the Excursion is to use the F250 code V or U for the front and code B or F for the rear.
I assume that the F250 spring rate would be considerably higher to increase the load capacity as much as this article suggests. It also makes more sense to me that a pickup (made to haul stuff in the bed) would have higher spring rates in the rear than an SUV. But again, I don't know much about these trucks yet, so I am trying to learn as much as possible and figure out what sources of information are credible. On that note, is there anyone in the mid-Atlantic region that has converted to F250 springs and is willing to give me a ride? Could be worth a 6 pack!
I'm in the very SouthEast corner of PA, not too far from Northern MD near the Bay. My EX has modded X and modded B codes and is available for test rides.
It hasn't been just wander. It was partially wander and partially nearly losing control going over bumps. That is a combination of bad shocks and wander. My desire to go to different springs is to increase the ability to safely tow. I was basing my statements from this (from SD Truck Springs):
Ford Excursions were built based on the Ford F250 however, they put lighter springs on them to increase ride comfort and have them drive more like a car or SUV then a truck. This becomes an issue for drivers who purchased the Excursion for towing purposes and need a heavier weight capacity. Ford Excursion springs have around a 1980lb capacity per side in the front and 2275lb capacity per side in the rear, the F250 springs on the other hand will give you between 2030lbs and 2630lbs per side in the front and 3000lbs per side for the rear, this is a substantial upgrade. When researching Ford Leaf Springs you will see a lot of information about spring codes. The most common switch for the Excursion is to use the F250 code V or U for the front and code B or F for the rear.
I assume that the F250 spring rate would be considerably higher to increase the load capacity as much as this article suggests. It also makes more sense to me that a pickup (made to haul stuff in the bed) would have higher spring rates in the rear than an SUV. But again, I don't know much about these trucks yet, so I am trying to learn as much as possible and figure out what sources of information are credible. On that note, is there anyone in the mid-Atlantic region that has converted to F250 springs and is willing to give me a ride? Could be worth a 6 pack!
First off that bit of misleading marketing would prevent me from using them as a supplier. ( so lame, but now I know the source of where people come up with that idea which gets repeated around here all to frequently )
Those numbers are TOTAL capacity which is calculated as: Travel x Spring Rate = Capacity.
(using their incorrect numbers)
Excursion
Rear Spring capacity 2275 / 5.5' of travel = 413 pounds per inch.
F250
rear spring capacity 3000 / 8' Travel = 375 pounds per inch
But like I said those numbers in themselves do not tell the whole story because the F250 spring is a 2 stage spring and when used on a Excursion you remove the secondary leaf ( referred to incorrectly as a "overload" ) and replace it with leafs from the excursion.
In the end these B mod springs are a single rate spring like the stock excursion and have the same spring rate as the stock excursion. what you have done is increased the travel to the original 420 pounds per inch and now the total capacity is 6720.
now that ends up working ok but is not ideal because the total spring capacity exceeds the rear axles weight rating which isn't a huge deal because the reality is the you will never put that much load on it but that also means you are ridding around with stiffer springs then you really need. So back full circle to my previous statement, use a longer travel spring with a lower spring rate then the stock Excursions 420 pound per inch rate.
I have never used these guys products but many on this forum have and from what I can see and read he has it pretty well figured out. ( unlike whom ever wrote that nonsense you copied ) Leaf Springs and Suspension Parts by Auto and Truck Springs
partially nearly losing control going over bumps. That is a combination of bad shocks and wander. My desire to go to different springs is to increase the ability to safely tow.
agreed on the bad shocks, I would also be willing to bet that the very important front bump stops are wasted or completely missing on your Ex.
FWIW, a stock ride height Ex with stock suspension travel but everything in proper order does tow its max GVWR decent and most would have no complains at all with it. But it can also be improved upon and going to a longer travel spring is one way to do that.
... I do have a load leveling hitch. Honestly, I didn't expect to have to use it only pulling 7k lbs though. .... I do plan to use the load leveling hitch though.
@Rcarpen22 , do you have a copy of the Ford towing guide for your Ex?
If you don't see my signature below for the link.
If you are having problems getting a copy for the 2001, Send me a PM and I can get you a pdf. The 2001 model was rated differently for towing limits than later models.
Thanks for the great info all. There is a lot of knowledge on this site.
Tom, looks like you are bout 2.5 hours from me. If I get over your way, I will definitely send you a message. Thanks!
Bion, actually, I can't figure out how to send a PM (is there a required post count?). I'll keep trying, but I was not able to find the towing guide for 2001. I found parts of it through Google search, but if you have a pdf that would be great.
Pirate4x4, Can you explain a little how they get more travel out of F250 springs using the same dimensions? I would think they would have to be longer necessitating mounting point mods, longer shackles, etc. I assumed that since they are the same physical size, they would have to have higher k value. Seems not to be the case, but I'm still missing a piece of the puzzle. Also, more reading has uncovered possible rear steering effect contributing to the issues. Seems like track bars might be a good mod. The landyot ones seem popular. From what I've read, it looks like it might be a different person making/selling them now. Thoughts on those? My plan is still to remove the RAS today or tomorrow, drive around some, and then get accurate measurements on ride height.
Thanks,
Rob
Landyots, rear steer..... man you are going down every rabbit hole that has been dug up since the Excursion has been made.
you seem pretty good at search so I am sure you can find my prior musings on Landyots and rearsteer so let me sumerize.
Landyot guy made up some BS therory about rear steer to sell his horribly designed product during a time when it was not common knowledge what the real issue was, sadly his “rear steer” therory has lingered on the Internet. Bottom line, unless you twist the axle housing his idea is nonsense.
Top spring is a clip from the Excursion blueprint, second is the F250
As you pointed out the length of the spring when flat is the same at 1475mm
the difference is the amount of arc in each spring shown as the free length, the f250 has more arc and has longer to travel before it is flat.
( flat is typically the point at which manufactures set up a spring to deflect to )
Might also want to check the hitch rating since they upgraded to bolts that added extra hitch capacity in later years. Changing those bolts is supposed to be an easy upgrade. If price isn't of concern and safety is, get a Hensley Arrow or ProPride hitch and the ATS spring upgrade from Junior at ATS.
I confess I got my front X codes from SD Truck Springs, and the springs are fine but the u-bolt shennigans they pulled (after three WRONG semi-round sets shipped what showed up as round only) had me fit to be tied and finally I called ATS and got the front semi-round bolt sets from them (correct the FIRST time).
Between that time I was re-using my rust free fron u-bolts while that issue was sorted out and also ordered the mod rear springs from ATS to match the x codes...and the ride height is perfect. The only other thing to mention is that I would have added an additional rust proofing paint job on the rear springs as they had only one trip into the salt belt and started showing signs of surface rust.
Since I dug out the blueprints lets take a look at the graphs from doing spring rate/load calculations.
Top pic is the Excursion graph
Take a look at the first segment labeled curb, this is your excursion at ride height and no payload.
the takeaway is the spring compression from free length to curb is 3.1" requiring 1280 lbs giving it a spring rate of 412 pounds per inch
bottom pic is the f250
takeaway is free length to curb is 2.4' requiring 783 lbs ( because the f250 doesn't weigh as much ) giving the first stage of the spring a rate of 326 pounds per inch.
now recall when I said the f250 was a multi stage spring ? look at the graph and you can see when the auxiliary spring kicks in and how it works with the truck style payloads.
So, 182.09mm (7.17 inches) of travel b/t free height and rated load for F250 vs 141.17mm (5.55 in) for Ex. Also, F250 is progressive rate spring. So, in theory, for an F250 spring, if I pull a trailer with a tongue weight of (let's assume) 1100lbs (trailer plus some stuff in the back of the Ex over the axle contributing some additional load) then the spring should deflect approximately 3.2 inches according to the graph. Also, that gets you into the progressive spring rate where deflection slows as load increases. Actually, I take that back. The graph, I believe is for a single spring, so deflection for each spring would be about 1.7 inches and you do not exceed the transition load. So if ride height is set to 24" in the rear as standard, would be 22.3" or so with the trailer and gear, which would actually make it slightly lower than the front at 23" stock height. Perhaps ride height with F250 springs would be a little higher. I can look that up. Thanks for the blueprints and graphs. That is great info. Also, you were right about the front bump stops. Passenger side is perfect. Driver side is gone (as in not present at all). I'll replace that.
I didnt check your numbers ( yet ) but it sounds like you get the jist of it.
but remember, when people do the f250mod springs, they remove the very bottom auxiliary spring which is what gives the f250 a secondary spring rate, Then they add the bottom 2 leafs from the Ex which then gives your modified f250 spring about the same spring rate as the stock excursion spring.
i say about because i calculated the figures off individual springs but you have to keep in mind that the Ex and the f250 have diffrent arc’s so there is going to be some funky binding going on. You would need to put them in a test jig and measure to get actual.
I have never ever seen ATS springs in person so I can not say how they build theirs.
Numbers for the F250 spring will be off as I realized that the curb load is higher on the Ex (obviously since the F250 bed would be much lighter than the roof, seats, hatch etc. of the Ex). I'll recalculate once I actually need to. Need to use the curb load from the Ex and plug it into the graph for the F250.
06-07-2018, 01:04 PM
