At what point do you replace leaf springs?

skiznits

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For awhile now I've been wanting to replace the stock springs but I'm not sure why. There is no real good data to support this and I think I may just be tossing away money.

113k miles on stock 1991 4.0 are the current specs. I have 30s on it but tires need replacement pretty bad, I don't like going over 45mph in it.

The springs look flat but I think that's normal. I even measured the rocker to ground and it's about 18" which sounds normal.

Was thinking that a new set of heavy duty stock from Dayton or Dorman may give it a tiny 'lift' and fit some new 30s better and not have driveline issues( I've been there before with my XJ).

However, now thinking the money perhaps better spent on inevitable issues like water pump or ignition stuff like I've read in other posts. Steering is super loose prob need new tie rods etc.
 

Gilaguy23

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I personally would not buy HD springs,to crappy of ride. Yes, the OEM's are basically flat. If your looking for the best ride you can get mst say OME are the way to go and they add a small lift as well. Stuff like rough co and ebay or amazon wong fu brand will have you hating life. Just remember every mod creats another problem or short comming....just saying.
 

machoheadgames

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Stock springs are basically 100% flat. They have a very teeny tiny arch to them. Most people think their springs wore to be that way, nope. The OEMs are actually pretty good at staying stock height long term. I have never seen one negatively arched.

Anyways, if you want a good ride, go with old man emu. Haven’t found anything else that rides as well. But if you don’t need high height, the stock springs work fine. You can significantly improve stock ride quality as well by changing the shocks.
 
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skiznits

skiznits

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The OEM aftermarket stock springs choices are somewhat limited. I will hold off on that until later notice. I need to investigate but I think their version of heavy duty isnt all that HD but I need to research it. Hard to get all the spring rates side by side.

I already replaced the shocks w some KYB and helped a lot. Just need some tires now.

I had OME shocks on my XJ with some Rusty's springs. Before that was Procomp and those were 💩.

Anyway sounds like I got some more time but if the 30s don't fit nicely then I will revisit.
 

Stoopid Jeep

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The OEM aftermarket stock springs choices are somewhat limited. I will hold off on that until later notice. I need to investigate but I think their version of heavy duty isnt all that HD but I need to research it. Hard to get all the spring rates side by side.

I already replaced the shocks w some KYB and helped a lot. Just need some tires now.

I had OME shocks on my XJ with some Rusty's springs. Before that was Procomp and those were 💩.

Anyway sounds like I got some more time but if the 30s don't fit nicely then I will revisit.
Not for nothin, but do you really need/want heavy duty springs?
The OME light load springs on my yj ride so nice, it amazes me. They don't even squat much with the hard top on.

It's a jeep, what are you hauling to justify heavy duty springs? They will likely make it ride rough as hell.

Just my perspective.
-Russ
 
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skiznits

skiznits

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Yes.I definitely don't need HD stiffer stuff. However, inventory for 'stock' stuff is low and they pretty much only have the HD spring for the rears left for USA made items. So I almost feel like hands tied to get the HD front also.

I'd use OME if they had a stock or 1" lift. Imma put the spring replacement on back burner. In the meantime I will check spring rates etc between a few of the more common kits just as a baseline.
 

machoheadgames

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I haven't looked very hard but I have not found much spring rate info out there for various brands. I do know that last I looked, the OMEs were around 140lb/in for the fronts and 185ish lb/in for the rears that they offer. I ran the rears on all 4 corners and it rides great. I believe stock spring rate is about 145 on all the springs.

Not sure about any other brand. What HD stuff are you referring to? When I lifted my YJ 3.5" years back, I went with BDS and used their heavy duty springs which is basically taking their front springs and putting them on the rear. They said those were the right choice for a hardtop and that it would still ride excellent without the hardtop on. It was like a damn log wagon, was horrible. Couldn't hardly drink a drink while driving without spilling it on yourself and it was just extremely bumpy, very uncomfortable. So I would highly recommend NOT putting HD rears on in any capacity unless you plan to have a bunch of weight back there all the time.

The OME stuff is solid, but if you want to stay stock height then just stick with what you got. There is practically no other "stock" option out there, the stock stuff is 1.5-2" minimum lift from everything I've seen, as evidenced by the fact that there is significant arch to them when installed.
 
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skiznits

skiznits

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Damn. Thx for the inputs.

I wish I had more real time info out there about those 'stock' Dayton leafs. Watch me get them and it jacks it up 2.5 inches plus a crappy ride. Exact opposite of what I wanted.
Kinda don't wanna go with crown or omix.
 

machoheadgames

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Not sure about Dayton offerings for the YJ but dayton springs on the Nissan frontier lifted the rear about 2" according to most who ran them.
 
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skiznits

skiznits

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Not sure about Dayton offerings for the YJ but dayton springs on the Nissan frontier lifted the rear about 2" according to most who ran them.
Dammit. Lol. 🤣
I'm guessing those were the OEM nissan replacements.

As always....sounds like this could be an expensive 'lets buy and see' process. Dang.

Even cheap springs are $$$ now.
 
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skiznits

skiznits

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Not sure about Dayton offerings for the YJ but dayton springs on the Nissan frontier lifted the rear about 2" according to most who ran them.
MACHO,
Oh I just re read your post.
Dayton and all the other 'stock' replacements offer a regular duty and a heavier duty(HD). They say they are 0 lift and replace the old springs. One just a little bit stiffer. Even quadratec has a few of these options and rock auto.

However, many of these companies do not have regular duty for the rears. Only the HD. There is actually one super heavy duty one listed for the rear even higher capacity than the reg HD.





I always wondered why the even offered a HD unless they put that on jeeps with 4.0 and hardtop. Local shop here in CA, deaver springs thinks I should go with the HD.
 
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skiznits

skiznits

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I went and did my homework and am reporting back.

Dayton springs and many others say the following for stock replacement:

FRONT
Regular duty 100 lb/in
Heavy duty 172 lb/in

REAR
Regular duty 130lb/in
Heaviest duty 254lb/in 🥵

They didn't have the lb/in... so I took the spring rating weight and divided it by the free arch height in inches. Hope that is close. But idk.

172 in the front seems sorta stiff. Then again there is an engine there.

I do have a hard top and a steel roof rack and slightly heavier rear bumper. So probably 250 lbs over stock configuration.

Not expecting many replies but thought I'd post what I found.
 
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Stoopid Jeep

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I went and did my homework and am reporting back.

Dayton springs and many others say the following for stock replacement:

FRONT
Regular duty 100 lb/in
Heavy duty 172 lb/in

REAR
Regular duty 130lb/in
Heaviest duty 254lb/in 🥵

They didn't have the lb/in... so I took the spring rating weight and divided it by the free arch height in inches. Hope that is close. But idk.

172 in the front seems sorta stiff. Then again there is an engine there.

I do have a hard top and a steel roof rack and slightly heavier rear bumper. So probably 250 lbs over stock configuration.

Not expecting many replies but thought I'd post what I found.
I have no idea what all those numbers mean.
I got squishy springs.
squishy springs=Jeep hauls ass on dirt roads, Russ doesn't spill beer 😁🍺
 
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