Coilovers and spring rate and ride quality

Deezus

New member
Having an argument about this with a buddy.
If I had 3 to 500 lbs in the back of my Jeep with a Evo coilover and some Hd springs would ride quality suffer, would I have sagging or when Jeep was unloaded would ride quality suffer. Thanks.

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13_gecko_rubi

New member
Depends what the secondary spring is so need to know both springs to calculate the active spring rate until the secondary is engaged.

To give you an idea.... The factory spring rate is around 120 lb/in.

If you have 300/300 springs, you active spring rate is 150 in/lb until secondary is engaged.

To find you active spring rate this is the formula:

(Top rate * bottom rate)/(top rate + bottom rate)

250/250 = (250*250)/(250+250) = 125
250/500 = (250*500)/(250+500) = 167

Once u hit the secondary stop then your spring rate is whatever the bottom spring is. If you get too far apart in springs it can be a nasty transition. Thinking the 250/500 above. Running along at 167 then when secondary hits, it jumps to 500. That's a nasty transition.

Again remember, factory is 120ish. Even most lift companies only go into the 130-150 tops range. Many folks WAY OVERSPRING coilovers.

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Deezus

New member
Depends what the secondary spring is so need to know both springs to calculate the active spring rate until the secondary is engaged.

To give you an idea.... The factory spring rate is around 120 lb/in.

If you have 300/300 springs, you active spring rate is 150 in/lb until secondary is engaged.

To find you active spring rate this is the formula:

(Top rate * bottom rate)/(top rate + bottom rate)

250/250 = (250*250)/(250+250) = 125
250/500 = (250*500)/(250+500) = 167

Once u hit the secondary stop then your spring rate is whatever the bottom spring is. If you get too far apart in springs it can be a nasty transition. Thinking the 250/500 above. Running along at 167 then when secondary hits, it jumps to 500. That's a nasty transition.

Again remember, factory is 120ish. Even most lift companies only go into the 130-150 tops range. Many folks WAY OVERSPRING coilovers.

Sent via....
My main question was concerning ride quality. I understand what your saying about spring rates but there's been a lot of talk of how ride quality suffers and you got to readjust and so on and I don't think that's necessarily true.
I've seen a lot of people on here and other places run them and was curious as to what there application and experience was with heavier loads.

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wayoflife

Administrator
Staff member
If you setup your coilovers to carry a load, your ride quality will feel harsh when unloaded. Does that help?
 

doubletapdaddy

Caught the Bug
Guess I should have just said that lol

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😅

I've got to tell you though the knowledge that you provide is invaluable. I've already taken a screenshot of your response. Good stuff right there.

Now when are those half doors coming out? Lol.
 

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Saddletramp

New member
Curious what EVO's "JL" bolt on kit comes with for the sake of comparison?

If I remember correctly fronts on the "JK" kit were 250/250 and rears were 200/250 out of the box.

I later changed my JK rears to 250/250 to accommodate for gear/tools weight in the rear.

King was great to work with, they sent me the 250 upper springs and credited me for the 200 springs after i sent them back to them.

Sorry, just bored and talking out loud, lol
 

doubletapdaddy

Caught the Bug
Curious what EVO's "JL" bolt on kit comes with for the sake of comparison?

If I remember correctly fronts on the "JK" kit were 250/250 and rears were 200/250 out of the box.

I later changed my JK rears to 250/250 to accommodate for gear/tools weight in the rear.

King was great to work with, they sent me the 250 upper springs and credited me for the 200 springs after i sent them back to them.

Sorry, just bored and talking out loud, lol

EVO JL bolt-on coilover coils:

FRONT
20190626_185934_copy_1280x960.jpg
20190626_235827_copy_1280x960.jpg

REAR
20190627_135435_copy_1280x960.jpg
 

13_gecko_rubi

New member
[emoji28]

I've got to tell you though the knowledge that you provide is invaluable. I've already taken a screenshot of your response. Good stuff right there.

Now when are those half doors coming out? Lol.
They are "coming soon" I promise. Later more thanks to COVID but not too long. Not helpful I know

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Exodus Jeeps

Advertiser
Supporter
Lol, well in all seriousness there’s that too.

I also think I remember the JK kits were 2.0 and the JL’s are 2.5 which I’m sure factors into the difference too.

Just curious comparing the kits, getting itchy fingers on going with the JL package.


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I’ve been running the coilover kit on the JT since the beginning but we immediately changed spring rates since the kit was set up for the lower lift heights, and nobody (other than Jeep) had installed that kit on a JT yet. We have them dialed in pretty spot on to lower it down an inch and have an extremely nice ride even without long arms. I think the 2.5’s contribute a lot to that. For 90% of the people out there that kit is going to be more than enough.


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