Getting Ready to Order Rear Springs

[Bruce1954]

I was about to order new Bs for the rear but I have been looking at the 04 and up rears and they have changed as we know.
Thought I would do a little research first to see what the best fit for a family oriented all use X would be.
It got interesting as well as I need some help with Codes and matching rates. So I though I would post what I had and go from there.


From 02 info we have posted prior from Ford Data:
As far as I know this is the same 99 to 03

<font class="small">Code:</font><hr /><pre>

Super Duty Rating @ Number Total Overall Rate Each
pickup Ground of Thickness Length Width (lbs. per in./ @ pad (lbs.
Series/Model (lbs.) Leaves @pad(in.) inches spring)(1)(2) per spring)

F250/350SRW 6830 5 2.94 58.1 3.00 320/670 2998
F-350 DRW 8250 5 2.32 58.1 3.00 350/730 3626

(1) Pickup and Box Delete models include two-stage, variable rate springs.
Chassis Cab models and Class A Motorhome Chassis
include single-stage, constant rate springs.
.
.
SPRING SPECIFICATIONS — AUXILIARY REAR LEAF USAGE AND RATINGS
.
Main Spring Compined Auxiliary Spring Main + Aux +
Super Duty Rating @ Ground Nominal Rating Each@ Unsprung Wt. Combined
Series/Model (LH+RH)(lbs.) Pad (lbs.) Rating @ Ground (RH+LH)

F250/350SRW 6830 694 8218
F-350 DRW 8250 694 9638

</pre><hr />



We know these to be the B and C code springs With or without overloads
We know the overload/aux springs cause problems and may hit the rear AC lines.


04 Data is below (Thanks to and older post by ExcursionPSD)

<font class="small">Code:</font><hr /><pre>
.
SPRING SPECIFICATIONS FOR REAR LEAF WITH AUXILIARY
.
Combined Deflection Rating
Super Duty Rating @ Number Total Overall Rate Each
pickup Ground of Thickness Length Width (lbs. per in./ @ pad (lbs.
Series/Model (lbs.) Leaves @pad(in.) inches spring)(1)(2) per spring)

F250/350SRW 6830 6 3.86 58.1 3.00 320/670/1209 3603
F-350 DRW 8250 6 3.95 58.1 3.00 350/730/1270 4187
.
.
NOTES
(1) Pickup specs are for two-stage(auxilary), variable rate springs.
(2) Lists first stage/second stage/third stage as applicable.
(3) Auxiliary rear springs are not standard with 5.4L engine SRW applications
and are available with certain option packages only
(Effective 12/1/03, auxiliary rear springs will be deleted as standard on all
SRW pickup models regardless of engine and will be available
with certain option packages only).
</pre><hr />



05 Data is below

<font class="small">Code:</font><hr /><pre>
.
SPRING SPECIFICATIONS FOR REAR LEAF WITH AUXILIARY
.
Combined Deflection Rating
Super Duty Rating @ Number Total Overall Rate Each
pickup Ground of Thickness Length Width (lbs. per in./ @ pad (lbs.
Series/Model (lbs.) Leaves @pad(in.) inches spring)(1)(2) per spring)

F250 7000 6 4.18 58.1 3.00 330/650/1290 3133
F-350 SRW 7000 6 4.18 58.1 3.00 330/650/1290 3133
F-350 DRW 9000 6 4.37 58.1 3.00 457/902/1422 4024
.
.
NOTES

(1) Pickup and Box Delete models include two-stage, variable rate springs. Chassis Cab models and Class A Motorhome
Chassis include single-stage, constant rate springs.
(2) Lists first stage/second stage/third stage as applicable.
(3) Auxiliary rear spring available and included with Camper Package, Heavy Service Suspension Package, Snow Plow Prep
Package and Heavy Service Package For Pickup Box Delete only.

</pre><hr />



06 Data is below

<font class="small">Code:</font><hr /><pre>
.
SPRING SPECIFICATIONS FOR REAR LEAF WITH AUXILIARY
.
Combined Deflection Rating
Super Duty Rating @ Number Total Overall Rate Each
pickup Ground of Thickness Length Width (lbs. per in./ @ pad (lbs.
Series/Model (lbs.) Leaves @pad(in.) inches spring)(1)(2) per spring)

F250 7000 6 4.18 58.1 3.00 330/650/1290 3133
F-350 SRW 7000 6 4.18 58.1 3.00 330/650/1290 3133
F-350 DRW 9000 6 4.37 58.1 3.00 457/902/1422 4024
.
.
NOTES

(1) Pickup and Box Delete models include two-stage, variable rate springs. Chassis Cab models include single-stage,
constant rate springs.
(2) Lists first stage/second stage/third stage as applicable.
(3) Auxiliary rear spring available and included with Camper Package,
Heavy Service Suspension Package, Snow Plow Prep
Package and Heavy Service Package For Pickup Box Delete only at Job# 1. Auxiliary rear spring available and included with
Camper Package and Heavy Service Package For Pickup Box Delete only at Job# 2.
(4) Auxiliary rear spring will be deleted as standard and included with
Camper Package and Heavy Service Package For Pickup Box
Delete only at Job# 2.
(5) Standard and available at Job# 2

</pre><hr />

Looks like things stayed the same 05 to 06 but the notes changed and apparently
who gets what may have been adjusted, I have not read the notes sections enough
times to figure it out. Apparently the notes for 05 were a bit unclear. I know
I had hard time with them but I am sure any salesman can get it on the first read and advise correctly. [img]/ubbthreads/images/graemlins/biggrin.gif[/img]

Any way the 05 06 variable rates 330/650 are looking good to me with the X at 410 to start it makes some sense.

To me ideal would be; rear sits 1" above front with bags at 5PSI and 1/2 tank with about an inch of travel or a bit
more prior to the variable starting to kick in. This may require a spacer between the mains and the variable rate bottom
leaf since the X is so much heavier in the rear than the PU.

What do you all think so far?

As you know I am working toward the perfect all around non lifted using factory
parts X I can come up with since
I will be driving this thing for a good while.

Bruce

[housedad]

I see that the thickness of the springs has changed also.

2004 3.86"

2005 4.18"

2006 4.18"


I'll give it a try and see if I can wrap my brain around this:

I do not know the thickness of the auxilliary leaf so I cannot compare the the '02 data.

Comparing the 04 springs to the 05/06, the 05/06 springs may put you barely a little higher initially,with a 10 lbs./inch higher, but the overall sag would be worse, as the second stage is 20 lbs./inch less. That would leave you with a total deflection rate of -10 lbs/inch after it hits the second stage.

This seems to bear out since the 05/06 springs are rated for a total of 3133 lbs per spring while the 04's are rated at 3603 per spring.

Staying with the 04 springs would net a little more sag initially, but would be bolstered when the hit the second stage.

I hope I got that right. PLEASE correct me if my thinking is off.

I'm kinda hoping that a light first stage, combined with the higher arch., would allow airbags to make up the difference in height without a terrible ride. Unfortunately, I know it won't. It would require a very light first stage, I'm guessing &lt;250 lbs./inch

I also wonder, with going to a two stage with a significantly lighter first stage,such as the B codes, would increase spring wrap,
considering that the F250 springs were designed to give good ride while unloaded, whereas putting them on the Excursion is somewhat equivilant to a "loaded" condition. Do the B springs increase it? That first leaf should be able to twist quite a bit more than the stock springs. Landyot to the rescue on this.


Maybe the ideal setup would be a 350 /360 first stage, and a 650 to 670 second. If we could only pick and choose.....

[housedad]

Of course, all of the above I said about more sag was considering no airbags. With the airbags, then it does start to make sense, as the overall ride would be a bit plusher, but not bouncy.


Maybe I'm just confusing myself........ [img]/ubbthreads/images/graemlins/confused.gif[/img]

[STR0K1N]

I'm not the best at figuring out all of these spring conversations but could someone please suggest a code and year for me to get. I am wanting a fairly stock-like smooth ride with the highest height increase possible. It doesn't have to be quite as smooth riding as stock but i don't want it to ride as rough as a F-350 DRW unloaded. Any suggestions would be greatly appreciated.

[Bruce1954]

HouseDad

I think you are on the right track here is what I think has changed. I am hoping some of our SD pick up readers can verify this.

99-03 had the B codes with an overload/Aux spring on top
When these are used on an X most have left off the Aux spring but have had good results and axle wrap has not been a problem.

04 and I am guessing here looks like it could have been the same BASE B code spring with a variable rate leaf added to the bottom and some got the overload Aux spring on top.


05-06 same as 04 but new specs on the springs or are the springs the same and they were re-rated?? or both just bolting a variable rate leaf to the old B code could bring it up 10# per inch I would think and the variable rate leaf is easy to adjust and play with on its own.

Any one out there that can provide us with RGAWR (rear gross axle weight rating) for 04 and or 05 along with the corrisponding codes that would be most helpfull.

Looks like the stickers for these have moved from the drivers B pillar to the back edge of the drivers door and now give 4 spring codes.

As far and when you get into the variable rate ehn you put an 04-05 spring on an X that is the $64,000 question need to order some, measure some then calculate some.

"BUT I CAN DO IT" Just need to make sure I start with the righ codes.

Bruce

[Bruce1954]

[ QUOTE ]
I'm not the best at figuring out all of these spring conversations but could someone please suggest a code and year for me to get. I am wanting a fairly stock-like smooth ride with the highest height increase possible. It doesn't have to be quite as smooth riding as stock but i don't want it to ride as rough as a F-350 DRW unloaded. Any suggestions would be greatly appreciated.

[/ QUOTE ]

Sounds like you want to use Bs Cs (Cs are DRW springs) and taller blocks

Has anyone put C codes on aN X ?????


Bruce

[fordmastertech]

I ended up with V code fronts and B code rear minus the aux leaf as it will not work on a X. I first put the fronts in with some straight F350 blocks and had a drive line vibration. I put some 2 degree caster wedged under the blocks and it was ok after that. All this was done with the stock rear springs. I ran it like this for about a year before messing with the rear springs.
The next step was the 03 and down B code rear springs with the original rear blocks and it was a little low in the rear with the V code front springs with a years worth of sag in them for my liking. I got some of the F350 tapered blocks and put them in and it looks much better. In all the 03 B code with the F350 blocks is about 3/4 to 1 inch higher than the stock Excursion spring with the F350 block. We will see how it settles as time marches on. I do notice more height gain with the B codes vs the stock Excursion springs when the fuel tank is nearing empty. The adjustable Rancho shocks capped off the deal and they are a nice towing shock which can be backed down when empty. It tows, rides, looks and handles much better than the original suspension with 75k miles on it.
I also spent way more time than I want to admit to looking at the trucks on the lot, searching the spring information provided by Ford and the charts you have shown above, searching the parts and the Ford spec books and was almost going to use the later 05 and up B code rear springs. I felt with the weight of the Excursion's rear end that it would push right through the first spring stage and use up a lot of the second stage. I assume they get the final stage with the aux over load spring and if I remember correctly the 05 and up aux springs looked thicker but don,t hold me to this. I figured the heaver second stage 03 and down springs would work better for the Excursions heavy butt. I was thinking about air bags but the ride was pretty bouncy when empty on a older Ford van I have even with the Rancho shocks I am running on it turned up all the way.
Everything is a compromise but this setup has worked out for me and my needs.
FMT

[Bruce1954]

FMT, do the 03 and down have a variable rate spring on the bottom??

I thought they were a single rate with an aux/overload on top that requires the extra brackets on the frame rail.


Thanks for the info, this is the info I am trying to assemble for all of us.

Looking more at the DRW springs if the variable rate from the SRW could be used.
Just don't know yet. Hve to look at some trucks as you did.

Bruce

[fordmastertech]

[ QUOTE ]
FMT, do the 03 and down have a variable rate spring on the bottom??


[/ QUOTE ] I was not able to find that information but if memory serves me correctly the bottom spring leaf looked different on the newer trucks. I will have to look on the lot tomorrow at work if I have time.
This spring stuff can get confusing and very time consuming. Putting them in is the easy part.
FMT

[rechinca]

As I am looking into this same thing for mine, I will try and and more muck to the confusion. It would seem the 04 springs, based on ratings listed and the numbers game would be the better set up. They carry the individual stage ratings of the 03's but with a higher overall rating. I am not so concerned about the overall ride factor, if that was the case I would not have a truck based platform. I do however want the added rating for towing (not to exceed my vehicle ratings but to give the truck a better handling overall with the 30'TT attached.) I can get the 99-03 or the 04's without a problem right now, but I don't want to get stuck with something I won't use.

Am I missing something that I should remember from the older posts out there or does the 04 B code sound like the right idea? I will go find the circle on the wall to bang my head on while I wait for the responses! [img]/ubbthreads/images/graemlins/confused.gif[/img]

[Bruce1954]

[ QUOTE ]

This spring stuff can get confusing and very time consuming. Putting them in is the easy part.
FMT

[/ QUOTE ]

You have that right, I also do not want to talk about the hours I spent trying to figure out why the X front sat so low.

I debated for days if I should use Vs or Ws on my 02 I did not have any data to go on finally I deturming there was not only a spring rate differece as published but also there was a difference in the arch of the springs but had not idea how much so I ordered the Vs put them on documented everthing and the rest is history.

Now I am looking to do the same for the rear But I have a lot more to go on this time.

Back when I did the Vs on my 02 (Dec of 01) there were a couple of guys here who had used X springs and I thought they were to much.

I think you are right the 03 and below is a single rate spring the 04 and up have the added variable rate on the bottom I think this will work on the X however Like I said when will it get into the variable rate???????


BTW I put my 05 Ds next to my 02 Ds and they are the same, we thought there may have been a slight change however I think it was the change in the bump stop and the slightly lighter 6.0 that helped the Ds out a bit on the latter model Xs.

Bruce

[towrig]

Bruce,

If you look at the spring specs for 05 &amp; 06 again, you will see that there is a rating for the main leaf stack only for 250's in 05 and 250 &amp; 350's in 06.

Notice that the rates for the main leaf only 06 250 is 334/776. I would have assumed that the main leaf only stacks were the same as the mains with auxillaries, but this is not always the case.

I looked at a 06 F250 with "F" code rears. Main stack only, no aux spring. The variable rate leaf measured .80" thick.

There was a 06 250 next to it with "C" code rears (with aux spring). The variable leaf on that was .64" thick.

This would explain the significantly lower 2nd stage of the 330/650/1290 "C" code. The 4 leaves above the variable measured the same in each case.

Perhaps we can mix and match. Just more food for thought.

Rob

[Snowman269]

[ QUOTE ]
HouseDad

I think you are on the right track here is what I think has changed. I am hoping some of our SD pick up readers can verify this.

99-03 had the B codes with an overload/Aux spring on top and I am guessing here looks like it could have been the same BASE B code spring with a variable rate leaf added to the bottom and some got the overload Aux spring on top.


05-06 same as 04 but new specs on the springs or are the springs the same and they were re-rated?? or both just bolting a variable rate leaf to the old B code could bring it up 10# per inch I would think and the variable rate leaf is easy to adjust and play with on its own.

Any one out there that can provide us with RGAWR (rear gross axle weight rating) for 04 and or 05 along with the corrisponding codes that would be most helpfull.

Looks like the stickers for these have moved from the drivers B pillar to the back edge of the drivers door and now give 4 spring codes.

As far and when you get into the variable rate ehn you put an 04-05 spring on an X that is the $64,000 question need to order some, measure some then calculate some.

"BUT I CAN DO IT" Just need to make sure I start with the righ codes.

Bruce

[/ QUOTE ]

The B's have a large supporting bottom leaf which supports the spring pack under load, which virtually eliminates axle wrap. The stock G's don't have this leaf, they have the long leaf with a rubber stop &amp; are prone to axle wrap.

I use airbags to level X for towing and occasionally have the Bags up around 65psi. My original concern (theory) was the spring pack not being fully compressed &amp; the spring pack not being supported by the Large bottom leaf, which could allow axle wrap with the B's while towing since they could act like the G's in this situation. While I still believe this theory is possible &amp; in specific situations could cause some sway or instability, it hasn't been an issue for me whatsoever. I have towed over 16,000 miles since installing this setup and found the B's on the X to tow as solid as my F250. The only way I could think to improve towing stability is with an arrow hensley hitch or switching to a dually IMO &amp; I have no interest or need (it's currently easy to forget I'm towing a trailer at times &amp; that can be startling).

From what I can see, I'd buy the 04 F250F350srw rear springs if I would do it again, it's looks (by the numbers) to be an even better setup. But as you know, noone had any info on installing B's when I jumped with a leap of faith &amp; ordered them, not knowing the 04's &amp; 05's which were relatively new at the time were different from the 03 and older models.

Side note, the X tows so well, I have not used my F250 to tow since the spring swap, that is absolutely amazing, really!

Dennis

[towrig]

Snowman, I agree, the bottom leaf on the B's supports the spring pack under load, which virtually eliminates axle wrap. It is also the leaf that makes the spring pack a two stage, variable rate spring. Perhaps rising rate is a better way to look at it. I don't think there is a sudden change from 320 to 670 lbs/in. As the bottom leaf starts to come into contact with the main stack it provides more assistance until the full length is in contact, then you have the full 670 lbs/in rate (in the case of the B code).

What I am trying to figure out, is why the rating at each pad increased substantially in 03 &amp; 04, but the combined rating at the ground stayed the same as previous years. They must have included the auxilliary leaf in the rating at the pad in 03 &amp; 04, but not before or after. How else could we explain the large decrease at the pad in 05?

I have been thinking about this way too much. [img]/ubbthreads/images/graemlins/smile.gif[/img]

[DOC4444]

Bruce,

Does this mean you have given up going with new rear suspension with trailing arms and air bags?

DOC