Spring Rates

[AnnDee4444]

This is an old thread but was going to try to comment on here instead of starting a new one.

Does anyone have any info that compares spring rates of the major players? I see RK comments above. Those are from a year ago but I would assume that still stands. Any info on some of the other main vendors?

I have the Mopar 2" springs now. I may be in the market for stiffer springs due to possibly towing a small camper.

Thanks.

I don't have the exact info you are looking for, but I can offer an alternative. The 3.0 Mopar lift springs should be stiffer than the 3.6 & 2.0

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[Jeepjunkie]

This is an old thread but was going to try to comment on here instead of starting a new one.

Does anyone have any info that compares spring rates of the major players? I see RK comments above. Those are from a year ago but I would assume that still stands. Any info on some of the other main vendors?

I have the Mopar 2" springs now. I may be in the market for stiffer springs due to possibly towing a small camper.

Thanks.

 

[RubiRob]

This is an old thread but was going to try to comment on here instead of starting a new one.

Does anyone have any info that compares spring rates of the major players? I see RK comments above. Those are from a year ago but I would assume that still stands. Any info on some of the other main vendors?

I have the Mopar 2" springs now. I may be in the market for stiffer springs due to possibly towing a small camper.

Thanks.

Front / Rear

JLU Sport : 117 / 172
JLU Rubi : 125 / 174
Mopar lift : 132 / 181
Synergy : 120 / 175
Teraflex : 140
RK 2.5 : 137 / 175
RK 3.5 : 140 / 185
EVO Soft : they wouldn't tell me
Metalcloak: they wouldn’t tell me

 

[Halstem1]

Front / Rear

JLU Sport : 117 / 172
JLU Rubi : 125 / 174
Mopar lift : 132 / 181
Synergy : 120 / 175
Teraflex : 140
RK 2.5 : 137 / 175
RK 3.5 : 140 / 185
EVO Soft : they wouldn't tell me
Metalcloak: they wouldn’t tell me

Thanks! Evo wouldn't tell me either and I hadn't asked Metalcloak yet. This helps.

 

[RubiRob]

Thanks! Evo wouldn't tell me either and I hadn't asked Metalcloak yet. This helps.

You bet!

 

[Kevin Mojito]

We have posted it in a few other threads so here's a copy and paste from that, the first few lines refer to stock springs, then our springs:

“JLU Sport - 114/121 Front 171/174 Rear

JLU Rubicon - 123/128 Front 172/176 Rear

Mopar 2" Coils Lift - 131/133 Front 180/182 Rear

Our 2.5" Coil Spring Rates are as follows in the ride zone

137.5 Front at Ride Height

175 Rear at Ride Height

3.5" Coils are already coming in so we will give you those too

140 Front at Ride Height

185 Rear at Ride Height

The stock coils were dyno'd in house as well as at our spring supplier for confirmation of accuracy of rates."

Do you guys know what the 3.0 Diesel springs rates are ?

 

[Herson]

We have posted it in a few other threads so here's a copy and paste from that, the first few lines refer to stock springs, then our springs:

“JLU Sport - 114/121 Front 171/174 Rear

JLU Rubicon - 123/128 Front 172/176 Rear

Mopar 2" Coils Lift - 131/133 Front 180/182 Rear

Our 2.5" Coil Spring Rates are as follows in the ride zone

137.5 Front at Ride Height

175 Rear at Ride Height

3.5" Coils are already coming in so we will give you those too

140 Front at Ride Height

185 Rear at Ride Height

The stock coils were dyno'd in house as well as at our spring supplier for confirmation of accuracy of rates."

Have you dyno the 392 springs? If so, what is the rate? Thanks.

 

[TxJeepers]

Edit: added Teraflex rear rate based on the 3.5" springs

Front / Rear
JLU Sport : 117 / 172
JLU Rubi : 125 / 174
Mopar lift : 132 / 181
Synergy : 120 / 175
Teraflex : 140 / 170
RK 2.5 : 137 / 175
RK 3.5 : 140 / 185
EVO Soft : they wouldn't tell me
Metalcloak: they wouldn’t tell me

 

[AnnDee4444]

I've read that the 392 springs are "10% stiffer".

 

[GavinH]

Edit: added Teraflex rear rate based on the 3.5" springs

Front / Rear
JLU Sport : 117 / 172
JLU Rubi : 125 / 174
Mopar lift : 132 / 181
Synergy : 120 / 175
Teraflex : 140 / 170
RK 2.5 : 137 / 175
RK 3.5 : 140 / 185
EVO Soft : they wouldn't tell me
Metalcloak: they wouldn’t tell me

Just received my JKS 1.5 springs.
130 front 136 rear
Anyone know roughly the free length of jlur rear springs trying to see what these JKS are actually going to net me?

 

[AnnDee4444]

Just received my JKS 1.5 springs.
130 front 136 rear
Anyone know roughly the free length of jlur rear springs trying to see what these JKS are actually going to net me?

The range is pretty large. As an example, JL (2-door) rear springs have been measured between 14.125" - 17.5" free length.

Coil wraps, spring material, wire thickness, & vehicle weight also influence the final ride height... I doubt you'll ever get an accurate estimate off of calculations.

 

[GavinH]

The range is pretty large. As an example, JL (2-door) rear springs have been measured between 14.125" - 17.5" free length.

Coil wraps, spring material, wire thickness, & vehicle weight also influence the final ride height... I doubt you'll ever get an accurate estimate off of calculations.

Thank you I’m not sure why I’m sweating this small detail so much but I just can’t make up my mind if I should include my half inch teraflex spacer or just coils only. Plastic rear, stubby stamped steel front and 12k winch upfront. Spacer has me half inch lower in front rn so I feel I’ll need it with these new springs but with the rear only having 136 rating Idk how far that’ll drop. Front springs are 19 inches free length maybe a hair over like 19 1/8 and rear is 16 maybe a hair under like 15 13/16ths

 

[GrayWolf.Overland]

Spring rates gathered over time. Not a complete list, and some of this may or may not have changed as years progressed. Data on Clayton and Synergy are listed on their pages so they are accurate. JKS data is from a recent enquiry I made with them as I was shopping for a 2.5" coil spring (fall-2023)

Manufacturer	Option/Variant	Front lb/in	Rear lb/in
Jeep	JLU Sport	117	172
Jeep	JLU Rubicon	125	174
Jeep	Mopar 2" Lift	132	181
Teraflex	2.5"/3.5"	140	170
Teraflex	2.5"/3.5" HD	170	300
Clayton	1.5"	160	137 / 200 (dual rate)
Clayton	2.5"/3.5"	188	165 / 230 (dual rate)
Clayton	2.5" HD	N/A	165 / 285 (dual rate)
Clayton	3.5" HD	N/A	170 / 285 (dual rate)
Synergy	1"	95 / 120 (dual rate)	115 / 150 (dual rate)
Synergy	2"/3"	110 / 120 (dual rate)	140 / 175 (dual rate)
Synergy	4"	115 / 120 (dual rate)	120 / 180 (dual rate)
Rock Krawler	2.5"	137	175
Rock Krawler	3.5"	140	185
JKS	2.5"/3.5"	110 / 175 (progressive)	144 / 210 (progressive)
JKS	2.5"/3.5" HD	144 / 210 (progressive)	152 / 210 (progressive)
OME	2-2.5" Standard	135	160
OME	2-2.5" Medium	150 (bumper + Winch)	175
OME	2-2.5" Heavy	---	200

 

[AnnDee4444]

JKS data is from a recent enquiry I made with them as I was shopping for a 2.5" coil spring (fall-2023)

interesting... I've read that the JKS 1.5" is 130 in the front... slightly higher than the 2.5"-3.5". I Really wish companies would stop trying to hide this info.

 

[OminousSkitter]

When we talk about spring rates, are we talking about the spring rate* (also called the spring constant) in Hooke's Law: F = -kx? Of course assuming non-dual/triple rate springs.

If so, would that mean that two springs of the same rate would compress (x in the above) the same amount to the same static load regardless of other factors like unsprung length or number of coils? Or is this a case where the real world application conflicts with the science definition (which happens a lot)?

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