Lift Height Confusion

Calvin.8

TJ Enthusiast
Nov 11, 2018
124
Iola KS
Alright fellas, I'm kinda confused here. So I have a rough country 2.5 inch lift that was on my jeep when I bought it. I know it is a 2.5 lift because rough country doesn't sell a spring that is less than 2.5 inches, but when I measured my coil springs, here is what I found...
20190110_172902.jpg
20190110_172944.jpg
Is it possible for springs to sag down this much? I just added a winch so I was curious to see how far it lowered my suspension (I hadn't measured before, so I'm not sure if it was even at 2.5 to begin with. And now I'm confused that a spring has lost so much lift.
 

bobthetj03

vibrajeep
Supporting Member
Ride of the Month Winner
Feb 3, 2017
8,062
NorCal
I have no experience with RC springs, but I've read a lot of complaints about them sagging prematurely. Looks like you have a culprit there.
 

Chris

Administrator
Staff Member
Sep 28, 2015
35,369
Salem, Oregon
I too have heard of issues with RC springs sagging. While I don't have any first hand experience with this, I have heard it on multiple occasions.
 
OP
Calvin.8

Calvin.8

TJ Enthusiast
Nov 11, 2018
124
Iola KS
Welp, looks like I need some new springs then. Add that to the never-ending list.

I have a Savvy 1.25 inch BL shipping to me at the moment, so that should help out until I can get new springs. What springs would you guys recommend to go with the BL to get me somewhere between 3.5 and 4 inches of lift? I'm not sure how companies set up their springs such as they give more lift than what they say to make up for extra weight, or they give that much lift for a stock jeep. My major items of weight that I've added to my jeep is a Winch (around 80 lbs), rocker guards (about 60 lbs), and rear bumper (115 lbs). If that helps anything.
 
Last edited:

liquidfluidity

TJ Enthusiast
Apr 29, 2017
130
IA....
Maybe look into the Old Man Emu ZJ/LJ kit. The spring numbers are 934/949. Sounds like you're definitely hauling some weight. Might not net you quite the amount of lift you're looking for though....
 
OP
Calvin.8

Calvin.8

TJ Enthusiast
Nov 11, 2018
124
Iola KS
Maybe look into the Old Man Emu ZJ/LJ kit. The spring numbers are 934/949. Sounds like you're definitely hauling some weight. Might not net you quite the amount of lift you're looking for though....
Ya I've looked into OME, but realistically I want to make to make sure that I'm at least 2.5 inches (I've changed my mind that I want to be somewhere between 3.75-4.25). And it seems like those are only 2 inch springs. I am also afraid if I get a 3 inch spring, it will lift me more than that, and I'll end up with almost 5 inches of lift. Do you think my jeep weighs enough for a 3 inch spring?
 

Farmergreg

Just a "Web Wheeler"
Supporting Member
Mar 25, 2018
373
WC Indiana
I went thru the dilemma of springs height back in November. Since I tucked the transfer case, I wanted to limit the spring lift to 3".
Savvy wouldn't return emails regarding spring rates.
OME had various springs / rates but looked like 2.5" was the lift depending on weight then dial it in with shims.

Ended up with JKS JSPEC 3" progressive set. And I like them. Reasonable price. Known rates, great response from JKS when inquiring.
 
OP
Calvin.8

Calvin.8

TJ Enthusiast
Nov 11, 2018
124
Iola KS
I went thru the dilemma of springs height back in November. Since I tucked the transfer case, I wanted to limit the spring lift to 3".
Savvy wouldn't return emails regarding spring rates.
OME had various springs / rates but looked like 2.5" was the lift depending on weight then dial it in with shims.

Ended up with JKS JSPEC 3" progressive set. And I like them. Reasonable price. Known rates, great response from JKS when inquiring.
So the JKS JSPEC 3" springs didn't lift you more than 3"? And are their springs well known for not sagging? A tummy tuck is in my future as well so that is another reason I don't want the springs lifting me higher than 3"
 

Farmergreg

Just a "Web Wheeler"
Supporting Member
Mar 25, 2018
373
WC Indiana
So the JKS JSPEC 3" springs didn't lift you more than 3"? And are their springs well known for not sagging? A tummy tuck is in my future as well so that is another reason I don't want the springs lifting me higher than 3"
I think I put some numbers in my build thread. It did raise it slightly more. But I've driven and wheeled it some. I could remeasure it. Not sure about their reputation for sag as it seems to be a semi new product. They are a progressive spring IE closer coils at the top. Paired with rancho 5000X the ride is nice. (my daily is a 3/4 ton pickup, so I may be jaded!)

On edit: Looks like I put sitting 5 3/4" higher in my build thread. So I had worn down 31" tires and went to new 33" and my stock springs were original with 200K miles on them. Accounting for the tires, it does look like the JKS lifted it 4" over worn stock springs.
 
Last edited:

liquidfluidity

TJ Enthusiast
Apr 29, 2017
130
IA....
Ya I've looked into OME, but realistically I want to make to make sure that I'm at least 2.5 inches (I've changed my mind that I want to be somewhere between 3.75-4.25). And it seems like those are only 2 inch springs. I am also afraid if I get a 3 inch spring, it will lift me more than that, and I'll end up with almost 5 inches of lift. Do you think my jeep weighs enough for a 3 inch spring?
My Jeep is pretty light but I ended up with over 3" in the front and around 2.5" in the rear. It actually turned out pretty good. Just trying to tweak for a little more plush ride without sacrificing handling.
 
OP
Calvin.8

Calvin.8

TJ Enthusiast
Nov 11, 2018
124
Iola KS
My Jeep is pretty light but I ended up with over 3" in the front and around 2.5" in the rear. It actually turned out pretty good. Just trying to tweak for a little more plush ride without sacrificing handling.
Given that I have quite a bit of weight added to my jeep, I'm guessing that I should end up with right around 3" of lift then. And if it ends up being less I can add coil spring spacers.
 
Last edited:

jjvw

Your Jeep's name is Karen now.
Supporting Member
Feb 17, 2018
5,361
Colorado, USA
One of the frustrations you are seeing is that the advertised lift heights are very approximate and each manufacturer makes different assumptions of how much they think a Jeep will weigh when they design their advertisements.

If you know your sprung weights, you can make a reasonable prediction of what a linear rate spring will provide. Or if you know the lengths and rates of the springs you have right now, you can reasonably calculate your sprung weights.

When the coils are multi rate, then things get complicated.
 
Reactions: Calvin.8
OP
Calvin.8

Calvin.8

TJ Enthusiast
Nov 11, 2018
124
Iola KS
One of the frustrations you are seeing is that the advertised lift heights are very approximate and each manufacturer makes different assumptions of how much they think a Jeep will weigh when they design their advertisements.

If you know your sprung weights, you can make a reasonable prediction of what a linear rate spring will provide. Or if you know the lengths and rates of the springs you have right now, you can reasonably calculate your sprung weights.

When the coils are multi rate, then things get complicated.
How do I determine my current sprung weight or length and rates
 
OP
Calvin.8

Calvin.8

TJ Enthusiast
Nov 11, 2018
124
Iola KS
Unfortunately, I don't have those on my big list. And they are progressive rate, which makes the reverse calculation difficult.
So I am probably just going to have to wing it then.

Does OME have any 2.5-inch springs?
 
Last edited:

jjvw

Your Jeep's name is Karen now.
Supporting Member
Feb 17, 2018
5,361
Colorado, USA
So I am probably just going to have to wing it then.

Does OME have any 2.5-inch springs? I am confused on how the determine their springs
OME coils are linear rate. For example, the 2934 will compress 1" for every 160lbs placed on top of that spring.

Their free length is 20.8". If the result is a 14.5" tall 2934 spring at ride height, then that corner weighs about 1008lbs.
 
OP
Calvin.8

Calvin.8

TJ Enthusiast
Nov 11, 2018
124
Iola KS
OME coils are linear rate. For example, the 2934 will compress 1" for every 160lbs placed on top of that spring.
But since I don't know the rate of my springs, I can't figure out what that would do to my jeep then, correct?
 

jjvw

Your Jeep's name is Karen now.
Supporting Member
Feb 17, 2018
5,361
Colorado, USA
But since I don't know the rate of my springs, I can't figure out what that would do to my jeep then, correct?
Correct. Look at my edit above. If you start with a linear rate coil with known quantities, then you can do the math.
 
Last edited:
Reactions: Calvin.8