New spring time
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Tuned
Joined: Dec 2020
Posts: 338
Likes: 25
New spring time
So I have been trying to figure out a driveline vibration. My rear springs are almost completely flat and fronts same. I am looking to replace I was wondering what brands people have done in the past. 1999 f250 4x4 late build date
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,344
Likes: 5,941
From: Lake Hartwell, GA
I replaced my rear springs through SD Truck Springs many years ago and they are holding up great while towing the 5th wheel 90% of the time it is in the road.
ATS is a site sponsored and has made a lot of people happy too.
ATS is a site sponsored and has made a lot of people happy too.
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
I have a question I think is related to the topic here. Not wanting to hijack the thread so please let me know if I'm out of line.
So all the articles, threads, and shows I believe I've ever seen or read all say that a spring pack w/ thinner leaves and more of them will be stronger and ride better than a pack w/ fewer thicker leaves. If this is in fact true where are those options for aftermarket springs? I get the factory not using them from an economic standpoint plus they're trying to cast a broad net to appeal to more people, but the aftermarket is wide open. I know there has to be a break over point where to thin is just to thin, but I just had a look at the ats website and it's pretty much the same as everywhere else a 2 or 3 leaf pack up front between 3/8 and 5/8 thick leaves and the rears are like 4-6 leaves around 3/8-7/16. Instead of those 5/8 thick leaves on the X codes couldn't we use twice as many 5/16 and possibly end up with a smoother tougher spring?
So all the articles, threads, and shows I believe I've ever seen or read all say that a spring pack w/ thinner leaves and more of them will be stronger and ride better than a pack w/ fewer thicker leaves. If this is in fact true where are those options for aftermarket springs? I get the factory not using them from an economic standpoint plus they're trying to cast a broad net to appeal to more people, but the aftermarket is wide open. I know there has to be a break over point where to thin is just to thin, but I just had a look at the ats website and it's pretty much the same as everywhere else a 2 or 3 leaf pack up front between 3/8 and 5/8 thick leaves and the rears are like 4-6 leaves around 3/8-7/16. Instead of those 5/8 thick leaves on the X codes couldn't we use twice as many 5/16 and possibly end up with a smoother tougher spring?
It's a Van Gogh
Joined: Feb 2010
Posts: 7,795
Likes: 1,326
From: Elk Grove, CA
I like the idea of more, slimmer leaves. Not familiar with any such builders tho.
Coil springs can be custom made for reasonable coin.
Coil springs can be custom made for reasonable coin.
Thread Starter
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Tuned
Joined: Dec 2020
Posts: 338
Likes: 25
I have a question I think is related to the topic here. Not wanting to hijack the thread so please let me know if I'm out of line.
So all the articles, threads, and shows I believe I've ever seen or read all say that a spring pack w/ thinner leaves and more of them will be stronger and ride better than a pack w/ fewer thicker leaves. If this is in fact true where are those options for aftermarket springs? I get the factory not using them from an economic standpoint plus they're trying to cast a broad net to appeal to more people, but the aftermarket is wide open. I know there has to be a break over point where to thin is just to thin, but I just had a look at the ats website and it's pretty much the same as everywhere else a 2 or 3 leaf pack up front between 3/8 and 5/8 thick leaves and the rears are like 4-6 leaves around 3/8-7/16. Instead of those 5/8 thick leaves on the X codes couldn't we use twice as many 5/16 and possibly end up with a smoother tougher spring?
So all the articles, threads, and shows I believe I've ever seen or read all say that a spring pack w/ thinner leaves and more of them will be stronger and ride better than a pack w/ fewer thicker leaves. If this is in fact true where are those options for aftermarket springs? I get the factory not using them from an economic standpoint plus they're trying to cast a broad net to appeal to more people, but the aftermarket is wide open. I know there has to be a break over point where to thin is just to thin, but I just had a look at the ats website and it's pretty much the same as everywhere else a 2 or 3 leaf pack up front between 3/8 and 5/8 thick leaves and the rears are like 4-6 leaves around 3/8-7/16. Instead of those 5/8 thick leaves on the X codes couldn't we use twice as many 5/16 and possibly end up with a smoother tougher spring?
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Hotshot
Joined: Mar 2014
Posts: 10,750
Likes: 1,065
From: Douglassville, PA
I found ATS accessible, knowledgeable and honest. You tell them what you are doing and they will customize a spring pack to suit your needs. One member here lives in AK and had them shipped to him. I expect that shipping was more than the cost of the product but that would be life in AK.
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Tuned
Joined: Apr 2021
Posts: 424
Likes: 97
I have a question I think is related to the topic here. Not wanting to hijack the thread so please let me know if I'm out of line.
So all the articles, threads, and shows I believe I've ever seen or read all say that a spring pack w/ thinner leaves and more of them will be stronger and ride better than a pack w/ fewer thicker leaves. If this is in fact true where are those options for aftermarket springs? I get the factory not using them from an economic standpoint plus they're trying to cast a broad net to appeal to more people, but the aftermarket is wide open. I know there has to be a break over point where to thin is just to thin, but I just had a look at the ats website and it's pretty much the same as everywhere else a 2 or 3 leaf pack up front between 3/8 and 5/8 thick leaves and the rears are like 4-6 leaves around 3/8-7/16. Instead of those 5/8 thick leaves on the X codes couldn't we use twice as many 5/16 and possibly end up with a smoother tougher spring?
So all the articles, threads, and shows I believe I've ever seen or read all say that a spring pack w/ thinner leaves and more of them will be stronger and ride better than a pack w/ fewer thicker leaves. If this is in fact true where are those options for aftermarket springs? I get the factory not using them from an economic standpoint plus they're trying to cast a broad net to appeal to more people, but the aftermarket is wide open. I know there has to be a break over point where to thin is just to thin, but I just had a look at the ats website and it's pretty much the same as everywhere else a 2 or 3 leaf pack up front between 3/8 and 5/8 thick leaves and the rears are like 4-6 leaves around 3/8-7/16. Instead of those 5/8 thick leaves on the X codes couldn't we use twice as many 5/16 and possibly end up with a smoother tougher spring?
one company online that advertises progressive packs is carli suspension systems. they don't offer 99 to 03 but 04 and up. i don't know the differences in 04 and up but everything if found listed on there site was for lifts. one might call and speak with them to see what they offer or if they can accommodate. the majority of my trucks run time is pulling a toyhauler camper. the new leaf spring pack from ats was a night and day difference for sure but i also added traction bars at the same time. expensive but worth every penny as they removed the sway created by the suction i get when semi's or large vehicles as such pass me on the innerstate.
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
i too searched for a progressive leaf spring pack to replace my f350 rears earlier this year. read some interesting articles and watch 2 video's on youtube. there is a company in Australia that seems to have it figured out after testing several combo's but shipping would be ridiculous lol. i understand the principal and it sounds like a good all around choice in theory but maybe a better shock choice might soften the ride on stock springs better then r&d on progressives. the trick will be finding a company that has the experience in r&d for a progressive pack that both smooths out the ride but that is still capable of handling the weight of a full load or camper, trailer etc. i spoke with 4 companies and didn't feel confident in there responses so i purcased a replacement pack from ats. sd spring were a tad cheaper but i have a close friend that bought replacement springs from them and they went flat with in the first year. he does not pull a very heavy toyahuler either and clearly not everyone's experience but he was done with sd springs at that point. he purchased a new set from inline suspensions locally and has been happy w/o issue since. i would've purchased locally as well but they were almost double ats's price and ats were more willing to discuss options, better customer service hands down.
one company online that advertises progressive packs is carli suspension systems. they don't offer 99 to 03 but 04 and up. i don't know the differences in 04 and up but everything if found listed on there site was for lifts. one might call and speak with them to see what they offer or if they can accommodate. the majority of my trucks run time is pulling a toyhauler camper. the new leaf spring pack from ats was a night and day difference for sure but i also added traction bars at the same time. expensive but worth every penny as they removed the sway created by the suction i get when semi's or large vehicles as such pass me on the innerstate.
one company online that advertises progressive packs is carli suspension systems. they don't offer 99 to 03 but 04 and up. i don't know the differences in 04 and up but everything if found listed on there site was for lifts. one might call and speak with them to see what they offer or if they can accommodate. the majority of my trucks run time is pulling a toyhauler camper. the new leaf spring pack from ats was a night and day difference for sure but i also added traction bars at the same time. expensive but worth every penny as they removed the sway created by the suction i get when semi's or large vehicles as such pass me on the innerstate.
The 03 to 04 suspension difference is the change to coils up front. The rears are the same until 08.
CNCFAB
Joined: Apr 2020
Posts: 4,874
Likes: 2,006
I thought all multi leaf spring packs were/are progressive. The shorter the leaves get the more difficult they are to flex, so as the spring compresses the spring rate becomes stiffer.
The 03 to 04 suspension difference is the change to coils up front. The rears are the same until 08.
The 03 to 04 suspension difference is the change to coils up front. The rears are the same until 08.
Tuned
Joined: Apr 2021
Posts: 424
Likes: 97
I thought all multi leaf spring packs were/are progressive. The shorter the leaves get the more difficult they are to flex, so as the spring compresses the spring rate becomes stiffer.
The 03 to 04 suspension difference is the change to coils up front. The rears are the same until 08.
The 03 to 04 suspension difference is the change to coils up front. The rears are the same until 08.
progressive was the wrong term, i meant parabolic.
Cargo Master
Joined: May 2018
Posts: 2,442
Likes: 993
i searched for a parabolic leaf spring pack to replace my f350 rears earlier this year. read some interesting articles and watch 2 video's on youtube. there is a company in Australia that seems to have it figured out after testing several combo's but shipping would be ridiculous lol. i understand the principal and it sounds like a good all around choice in theory but maybe a better shock choice might soften the ride on stock springs better then r&d on parabolics. the trick will be finding a company that has the experience in r&d for a parabolic pack that both smooths out the ride but that is still capable of handling the weight of a full load or camper, trailer etc. i spoke with 4 companies and didn't feel confident in there responses so i purchased a replacement pack from ats. sd spring were a tad cheaper but i have a close friend that bought replacement springs from them and they went flat with in the first year. he does not pull a very heavy toyahuler either and clearly not everyone's experience but he was done with sd springs at that point. he purchased a new set from inline suspensions locally and has been happy w/o issue since. i would've purchased locally as well but they were almost double ats's price and ats were more willing to discuss options, better customer service hands down.
one company online that advertises progressive packs is carli suspension systems. they don't offer 99 to 03 but 04 and up. i don't know the differences in 04 and up but everything if found listed on there site was for lifts. one might call and speak with them to see what they offer or if they can accommodate. the majority of my trucks run time is pulling a toyhauler camper. the new leaf spring pack from ats was a night and day difference for sure but i also added traction bars at the same time. expensive but worth every penny as they removed the sway created by the suction i get when semi's or large vehicles as such pass me on the innerstate.
one company online that advertises progressive packs is carli suspension systems. they don't offer 99 to 03 but 04 and up. i don't know the differences in 04 and up but everything if found listed on there site was for lifts. one might call and speak with them to see what they offer or if they can accommodate. the majority of my trucks run time is pulling a toyhauler camper. the new leaf spring pack from ats was a night and day difference for sure but i also added traction bars at the same time. expensive but worth every penny as they removed the sway created by the suction i get when semi's or large vehicles as such pass me on the innerstate.
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
I thought 03 was the last year of the front leaf spring, was it 04? Of course knowing Ford it was probably a mid year change or something, confusing the hell out of the aftermarket.
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,344
Likes: 5,941
From: Lake Hartwell, GA
Wise words are below...
Originally Posted by Y2KW57
What is the "they" that has no curvature?
The 2 stock springs? The 2 add on springs? Or the 4 springs (per pack) combined?
If you just meant the 2 stock springs, what kind of curvature are you expecting?
For the last 44 years (since the 1978 model year), Ford OEM front leaf springs have been either flat or slightly reverse arched (aka negative arch, where the middle of the spring over the axle may be level with or slightly higher than the end of the spring at the aft shackle).
The only positive arched front leaf springs on a Ford OEM light truck since 1978 were the late 80's and mid 90's F-Superduty chassis cab 2WD trucks with a drop center I beam solid axle.
Not since the "High Boys" of the early to mid '70s have Ford front leaf springs been positively arched (banana shaped, where the ends of the banana at the spring eyelets are higher than the middle of the banana at the axle).
Seeing a "flat" pair of OEM stock springs on a '99 up Super Duty does not indicate that the springs are "shot." The OEM springs were "flat" when these trucks were brand new. The only caveat is that the 1999 and 2000 models had a different type of front spring design than the 2001 through 2003 models, but the designs are interchangeable (new u-bolts required).
If the top 2 springs in the 4 leaf pack shown in your photo are OEM stock, and the bottom 2 leafs are aftermarket add ons, and you decided to shorten the length of the add on springs by cutting them, then it is possible to create a sudden stress riser in the OEM leaf pack.
This is less likely to happen if cutting only the bottommost leaf as shown in the photo in Post 1, where the leaf that is second from the bottom remains uncut.
But if the second from the bottom leaf were to be cut, then the third leaf from the bottom (which is the bottom leaf of the original OEM spring pack) would have a sudden transition from an area of support to an area of no support (at the line where the spring below it was cut). This could create a situation were instead of stress being gradually distributed throughout the spring, the stress instead becomes concentrated at the region that is less constrained (where you cut the spring beneath). That could lead to breaking the OEM spring.
The 2 stock springs? The 2 add on springs? Or the 4 springs (per pack) combined?
If you just meant the 2 stock springs, what kind of curvature are you expecting?
For the last 44 years (since the 1978 model year), Ford OEM front leaf springs have been either flat or slightly reverse arched (aka negative arch, where the middle of the spring over the axle may be level with or slightly higher than the end of the spring at the aft shackle).
The only positive arched front leaf springs on a Ford OEM light truck since 1978 were the late 80's and mid 90's F-Superduty chassis cab 2WD trucks with a drop center I beam solid axle.
Not since the "High Boys" of the early to mid '70s have Ford front leaf springs been positively arched (banana shaped, where the ends of the banana at the spring eyelets are higher than the middle of the banana at the axle).
Seeing a "flat" pair of OEM stock springs on a '99 up Super Duty does not indicate that the springs are "shot." The OEM springs were "flat" when these trucks were brand new. The only caveat is that the 1999 and 2000 models had a different type of front spring design than the 2001 through 2003 models, but the designs are interchangeable (new u-bolts required).
If the top 2 springs in the 4 leaf pack shown in your photo are OEM stock, and the bottom 2 leafs are aftermarket add ons, and you decided to shorten the length of the add on springs by cutting them, then it is possible to create a sudden stress riser in the OEM leaf pack.
This is less likely to happen if cutting only the bottommost leaf as shown in the photo in Post 1, where the leaf that is second from the bottom remains uncut.
But if the second from the bottom leaf were to be cut, then the third leaf from the bottom (which is the bottom leaf of the original OEM spring pack) would have a sudden transition from an area of support to an area of no support (at the line where the spring below it was cut). This could create a situation were instead of stress being gradually distributed throughout the spring, the stress instead becomes concentrated at the region that is less constrained (where you cut the spring beneath). That could lead to breaking the OEM spring.