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I have an 03 F250 with VA for springs. The driver side is a about 1/2 to 3/4 lower then the passenger side. There is no variance between the fronts.
I've been looking at different posts and see reference to B and C springs and then aftermarket 43-1261 and 43-1263.
I would like to get some new rear springs and add to the capacity. From what I can tell, here are the specs on the A/B/C springs (please correct me if I'm wrong)
A = 6,084 pounds @ground = F-250
B = 6,840 pounds @ground = F-350 SRW and some F-250s
Do B's really have 800 more LBS of capacity. When talking with ATS and reviewing their part numbers the B's have a 3000 pound rating (each) or 6,000 for a pair so not true B springs?
Also if going from A to B springs how much lift can I expect? Is the general consensus not to get springs from a junk yard?
Thanks, those sites have the same info as ATS. I guess there is not really correlation between aftermarket and OEM.
Not really. I got my rears from ATS. I forget what the base spring was but I had them add a leaf to the stack to give me something between two load ratings and I like it.
I have an 03 F250 with VA for springs. The driver side is a about 1/2 to 3/4 lower then the passenger side. There is no variance between the fronts.
I've been looking at different posts and see reference to B and C springs and then aftermarket 43-1261 and 43-1263.
I would like to get some new rear springs and add to the capacity. From what I can tell, here are the specs on the A/B/C springs (please correct me if I'm wrong)
A = 6,084 pounds @ground = F-250
B = 6,840 pounds @ground = F-350 SRW and some F-250s
Do B's really have 800 more LBS of capacity. When talking with ATS and reviewing their part numbers the B's have a 3000 pound rating (each) or 6,000 for a pair so not true B springs?
Also if going from A to B springs how much lift can I expect? Is the general consensus not to get springs from a junk yard?
Yes, Ford's F-350 SRW rear springs really do have 800 lbs (more accurately, 746 lbs) than F-250 rear springs, when combining both sides and remembering that this rating is measured at ground, which includes the unsprung weight of the axle. So this combined rating at ground is very useful for consumers and cops, because it is what is measured on a truck scale.
However, the springs themselves can be rated another way: at the pad. I think this is where you are confused about the ATS specs, which state that rating for each spring pack per side is 3,000 lbs, and your math says 3,000 plus 3,000 does not 6,830 make. But remember, the at ground rating includes the unsprung weight of the entire axle assembly. The at pad rating does not include the unsprung weight, and that is the difference you are seeing that is causing the confusion.
To ease your mind, the Ford OEM at pad rating for the F-350 SRW springs you are considering upgrading to is 2,998 lbs. Pretty much 3,000 lbs, just like the aftermarket spring rating you noted. And just to be absolutely clear, the Ford 2,998 lb rated at pad springs are indeed the same constituent springs that constitute Ford's 6,830 lb combined rating at ground.
For comparison, your original F-250 springs are rated at 2,670 lbs at pad, with a combined rating of 6,084 at ground. Obviously, 2,670 x 2 does not add up to 6,084, and the difference is simply the unsprung weight of the axle. The DOT can't verify compliance with spring capacity limits by attaching a contraption between the spring pad and axle perch, so we are provided ratings at ground that can be measured with a truck scale.
Comparing the physical attributes to the F-250 vs the F-350 SRW vs the F-350 DRW springs...
1. All three models of spring packs have 5 leaves each.
2. All three models of spring packs are the same length eye to eye (58.1")
3. All three models of spring packs are the same width (3.0")
4. The difference between springs is in the thickness of the leaves.
a. F-250 SRW = 2.12" total pack thickness (height) at pad
b. F-350 SRW = 2.14" total pack thickness (height) at pad
c. F-350 DRW = 2.22" total pack thickness (height) at pad
None of the foregoing thickness measurements include the auxiliary spring and spacer, if applicable.
Before changing from F-250 springs to F-350 springs, try to have a look at an F-350 with the exact same wheelbase, bed length, cab style, transmission, drive type (4x2 or 4x4) and number of doors that you have, and look at the driveline (rear propshaft). Look for double cardan versus single cardan joints, look at the slip joint and carrier bearing (if applicable) location, and look at the pinion flange / yoke style arrangement, and compare with your truck. Also look for blocks between the spring pad and the axle perch, and note the height of the blocks, and compare with yours.
In some cases, Ford made driveline component changes (wheelbase, bed length, cab style, and drive type depending) in step with spring rate and block changes in order to maintain optimum pinion angles based on the truck being loaded (and the springs deflected) a certain percentage (I was told the percentage by an engineer at Ford, but have since forgotten. I'm going to estimate that it was 66%).
As there are many combinations of wheelbases, bed lengths, cab styles, transmissions, and drive types, there is no way I can tell you which may differ and which may stay the same... but I can tell you that I have seen differences in drivelines, and the engineers at Ford also told me that there can be difference in the driveline when the topic of F-250 vs F-350 came up for discussion, and the purpose for the difference was maintaining pinion angles, and the reason for the difference was due to the anticipated attitude of the truck bed based on the deflection of the springs fitted.
Since, in this discussion with Ford, we did not specifically distinguish between F-350 SRW pickup, F-350 SRW box delete, F-350 DRW pickup, F-350 DRW box delete, and F-350 chassis cab... (yes, five different designations that can have unique rear springs, nevermind the wheelbase, cab style, or drive type)... some of the driveline changes I bring up may not apply to your F-250 pickup to F-350 SRW pickup comparison. But if I were in your shoes, I would at least look at a comparable model to make sure. FYI, F-350s with the box delete option were fitted with two stage variable rate rear springs.
You asked how much lift you can expect... is that why you want new springs? More lift? Or do you want less sag when loaded? Or both? If the "lift" aspect is not as important to you as the anti sag when loaded aspect, have you considered adding auxiliary springs in a second stage arrangement instead? You'll need new U bolts to change springs anyway... might as well buy the spacer, the aux spring, and two cleats for the frame, and then have something similar to a two stage spring of your own.
Adding Ford's auxiliary spring to your existing spring pack would give you a combined rating at ground of 7,120 lbs, which is more than bumping up to F-350 springs, and would require no other changes. You would have the benefit of having the most supple springs available in a Super Duty when empty, and still have an airless overload spring to kick in when loaded. If you want even more capacity, then F-350 SRW springs plus the Ford single leaf auxiliary spring would bring your combined rating at ground to 7,866 lbs.
Most of the aftermarket spring houses use the same supplier, so the catalogs between competing retailers will mostly end up being the same. Very few businesses are actually in the business of MAKING springs. Most spring companies advertising online are simply another reseller of the same imported products sold everywhere else... even if the retailer USED to forge their own springs out of the iron ore mined from the ground that their business was founded on in the 1800s. That's just the way of the world today, with globalized competition, where lowest price prevails.
So, if you want an aftermarket comparison of an auxiliary spring, here are the details for the Ford OEM auxiliary spring you can compare to:
1. Number of leaves: one (1)
2. Rating at pad: 518 lbs
3. Total thickness at pad of just the leaf: .47" (about 1/2 an inch)
4. Length (tip to tip, no eyes): 41.5"
5. Width: 3.0"
Finally, you asked about junkyard springs. That's something that will entirely depend on the specific donor vehicle. I wouldn't order junkyard springs sight unseen, or based on photos alone. I think I would want to see the vehicle they came from, and actually pull the springs myself, or at least be given the opportunity to pick and point if not allowed to pick and pull. Otherwise, springs are not so terribly expensive not to order new, and believe it or not, Ford's prices are not bad for springs, especially if ordered through a forum friendly discounting dealer.
Well, this turned out to be a much longer treatise on springs than I intended, but I hope it answered some of your original questions!
My F250 came with Aux springs on top of A leaf springs. However, I have air bags and when filled to level the truck (when towing the 5'er) the Aux springs never come into play. They have since been removed.
Im not interested in lifting the truck with new springs. If I gain an inch or so whatever, but that is not my goal or reasoning for new springs. Im more interested in replacing the tired old springs and like the idea of adding a few capacity pounds along the way i.e. B/C springs.
ATS did the say only difference between their B/C springs (43-1261 and 43-1263) is 1 1/2in high difference. Else the capacity at the pad is still 3000 pounds. They also said there B spring would be the same height as my stock A spring.
Yes, Ford's F-350 SRW rear springs really do have 800 lbs (more accurately, 746 lbs) than F-250 rear springs, when combining both sides and remembering that this rating is measured at ground, which includes the unsprung weight of the axle. So this combined rating at ground is very useful for consumers and cops, because it is what is measured on a truck scale.
However, the springs themselves can be rated another way: at the pad. I think this is where you are confused about the ATS specs, which state that rating for each spring pack per side is 3,000 lbs, and your math says 3,000 plus 3,000 does not 6,830 make. But remember, the at ground rating includes the unsprung weight of the entire axle assembly. The at pad rating does not include the unsprung weight, and that is the difference you are seeing that is causing the confusion.
To ease your mind, the Ford OEM at pad rating for the F-350 SRW springs you are considering upgrading to is 2,998 lbs. Pretty much 3,000 lbs, just like the aftermarket spring rating you noted. And just to be absolutely clear, the Ford 2,998 lb rated at pad springs are indeed the same constituent springs that constitute Ford's 6,830 lb combined rating at ground.
For comparison, your original F-250 springs are rated at 2,670 lbs at pad, with a combined rating of 6,084 at ground. Obviously, 2,670 x 2 does not add up to 6,084, and the difference is simply the unsprung weight of the axle. The DOT can't verify compliance with spring capacity limits by attaching a contraption between the spring pad and axle perch, so we are provided ratings at ground that can be measured with a truck scale.
Comparing the physical attributes to the F-250 vs the F-350 SRW vs the F-350 DRW springs...
1. All three models of spring packs have 5 leaves each.
2. All three models of spring packs are the same length eye to eye (58.1")
3. All three models of spring packs are the same width (3.0")
4. The difference between springs is in the thickness of the leaves.
a. F-250 SRW = 2.12" total pack thickness (height) at pad
b. F-350 SRW = 2.14" total pack thickness (height) at pad
c. F-350 DRW = 2.22" total pack thickness (height) at pad
None of the foregoing thickness measurements include the auxiliary spring and spacer, if applicable.
Before changing from F-250 springs to F-350 springs, try to have a look at an F-350 with the exact same wheelbase, bed length, cab style, transmission, drive type (4x2 or 4x4) and number of doors that you have, and look at the driveline (rear propshaft). Look for double cardan versus single cardan joints, look at the slip joint and carrier bearing (if applicable) location, and look at the pinion flange / yoke style arrangement, and compare with your truck. Also look for blocks between the spring pad and the axle perch, and note the height of the blocks, and compare with yours.
In some cases, Ford made driveline component changes (wheelbase, bed length, cab style, and drive type depending) in step with spring rate and block changes in order to maintain optimum pinion angles based on the truck being loaded (and the springs deflected) a certain percentage (I was told the percentage by an engineer at Ford, but have since forgotten. I'm going to estimate that it was 66%).
As there are many combinations of wheelbases, bed lengths, cab styles, transmissions, and drive types, there is no way I can tell you which may differ and which may stay the same... but I can tell you that I have seen differences in drivelines, and the engineers at Ford also told me that there can be difference in the driveline when the topic of F-250 vs F-350 came up for discussion, and the purpose for the difference was maintaining pinion angles, and the reason for the difference was due to the anticipated attitude of the truck bed based on the deflection of the springs fitted.
Since, in this discussion with Ford, we did not specifically distinguish between F-350 SRW pickup, F-350 SRW box delete, F-350 DRW pickup, F-350 DRW box delete, and F-350 chassis cab... (yes, five different designations that can have unique rear springs, nevermind the wheelbase, cab style, or drive type)... some of the driveline changes I bring up may not apply to your F-250 pickup to F-350 SRW pickup comparison. But if I were in your shoes, I would at least look at a comparable model to make sure. FYI, F-350s with the box delete option were fitted with two stage variable rate rear springs.
You asked how much lift you can expect... is that why you want new springs? More lift? Or do you want less sag when loaded? Or both? If the "lift" aspect is not as important to you as the anti sag when loaded aspect, have you considered adding auxiliary springs in a second stage arrangement instead? You'll need new U bolts to change springs anyway... might as well buy the spacer, the aux spring, and two cleats for the frame, and then have something similar to a two stage spring of your own.
Adding Ford's auxiliary spring to your existing spring pack would give you a combined rating at ground of 7,120 lbs, which is more than bumping up to F-350 springs, and would require no other changes. You would have the benefit of having the most supple springs available in a Super Duty when empty, and still have an airless overload spring to kick in when loaded. If you want even more capacity, then F-350 SRW springs plus the Ford single leaf auxiliary spring would bring your combined rating at ground to 7,866 lbs.
Most of the aftermarket spring houses use the same supplier, so the catalogs between competing retailers will mostly end up being the same. Very few businesses are actually in the business of MAKING springs. Most spring companies advertising online are simply another reseller of the same imported products sold everywhere else... even if the retailer USED to forge their own springs out of the iron ore mined from the ground that their business was founded on in the 1800s. That's just the way of the world today, with globalized competition, where lowest price prevails.
So, if you want an aftermarket comparison of an auxiliary spring, here are the details for the Ford OEM auxiliary spring you can compare to:
1. Number of leaves: one (1)
2. Rating at pad: 518 lbs
3. Total thickness at pad of just the leaf: .47" (about 1/2 an inch)
4. Length (tip to tip, no eyes): 41.5"
5. Width: 3.0"
Finally, you asked about junkyard springs. That's something that will entirely depend on the specific donor vehicle. I wouldn't order junkyard springs sight unseen, or based on photos alone. I think I would want to see the vehicle they came from, and actually pull the springs myself, or at least be given the opportunity to pick and point if not allowed to pick and pull. Otherwise, springs are not so terribly expensive not to order new, and believe it or not, Ford's prices are not bad for springs, especially if ordered through a forum friendly discounting dealer.
Well, this turned out to be a much longer treatise on springs than I intended, but I hope it answered some of your original questions!
Wow! Great informative Post. I learned something as well. Thank you sir.
So I did some playing around with the truck this afternoon. The rear is what is causing the issue for the lean. At a min, the B springs or 43-1261's should bump the capacity some and resolve the issue at hand.
However, before I purchase rear springs, I wanted to ask, do my front springs appear to be sagging? The truck does have a 3in hanger/shackle lift.
So I did some playing around with the truck this afternoon. The rear is what is causing the issue for the lean. At a min, the B springs or 43-1261's should bump the capacity some and resolve the issue at hand.
However, before I purchase rear springs, I wanted to ask, do my front springs appear to be sagging? The truck does have a 3in hanger/shackle lift.
Not really. My OEM springs arched like that as well. My ATS springs are a little closer to flat but still have a slight arch up also.
Old post but wanted to provide some real world numbers after swapping leaf springs and then adding a leaf. Note, my truck came stock with A code springs in the rear.
After swapping to 43-1261 ATS springs, I gained 1" of height in the rear and the truck still had a slide lean to the driver side by roughly 1/4 inch.
I then added in a leaf from ATS that added roughly 400 pound of capacity per leaf spring. From this, I gained 1 3/4" of height in the rear and I no longer have a lead to the driver side.
