Need some help with a coilover spring decision...

I need some opinions here. Been looking and racking my brain on what to do here. Ok so here`s what I got: Currently rig is a TJ, 110" WB, 43`s, Chevy TBI 350, 700R4, Atlas. I have 14" FOA`s all the way around. They all have the little helper spring up top. Everything I hear is if you don`t have to run them don`t. So that's what I`ve been trying to figure out. I have 2 FOX 2.0 with the helper spring already on them. They are stock valving at 50/70 and they have a 14" 300lb lower spring and a 225 12" upper spring. My buddy has been running them on the Front of his TJ (our rigs are very much alike) and they ride great but, are just a little soft on hard landings. I`m gonna put them on the BACK of my rig. I just bought 2 more Fox 2.0`s and had them valved 70c/50r and plan on putting them on the front of my rig. I was thinking I would run a 300lb lower spring and a 250 upper. I`m racking my brain on weather I can just put a 16" lower spring and a 14" upper spring and due away with the helper/triple rate set up or is that really gonna affect my ride height? I can buy the triple rate spring and run 14 lower and 12 upper just like whats going on the back but I just keep hereing if you can get away from that Do So as it really serves no purpose other than when the shock is extended. I`ve just been back and forth so I figured I`d post it up for some opinions. I really like my ride height as it sits now. That being said these FOA`s have the raised bottom spring seat and the FOX`s have the flat.

Heres pic of the Jeep just for reference.

Get rid of the triple rate setup. Run a 16" lower and a 14" upper spring. The longer springs allow for more preload, this will cause your suspension to push the tires down as the terrain changes. Your current springs seem to be very heavy. I think you can get a better ride quality with proper springs and valving.

RustyC said:

Get rid of the triple rate setup. Run a 16" lower and a 14" upper spring. The longer springs allow for more preload, this will cause your suspension to push the tires down as the terrain changes. Your current springs seem to be very heavy. I think you can get a better ride quality with proper springs and valving.

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This is exactly what I`ve been told and it makes good sense. The FOA`s are 2.5" coilovers where the FOX`s are 2.0. I actually really like the spring ride (its actually really smooth on the trail) but, the FOA`s leak and are soft when landing hard. I`m going to the foxs for the better shock and easier valving. Being the foas are a bigger coil would I get about the same spring ride out of a 250/300 with the smaller coils that are needed for the new foxs or is there going to be a difference due to coil size?

Here is a good place to start looking.

http://www.pirate4x4.com/forum/general-4x4-discussion/1074029-spring-tech-thread.html

Springs sound WAY to stiff.

RusyC is absolutely right. And you should have 2" of pre-load on the springs. Check this article, lots of great info from some very knowledgeable people. http://www.pirate4x4.com/forum/general-4x4-discussion/1074029-spring-tech-thread.html

The spring rate is not dependent on size. 2.0 vs 2.5. A 100 lb spring is always 100 lb not matter the i. d.

10-4 That's good to know for sure. I`m wanting to do an LS swap but have made my mind up to get these tuned like I want first. I know its hard to do but, I really want a nice mix between a rig that's pleasant to ride trails all day long and one that I can still haul ass around in and beat/jump a little.

Well it looks like you haven't talked to Kevo. Aka KMCMMN or whatever.. Just wait. He should chime in and set you straight.

kushKrawlin said:

Well it looks like you haven't talked to Kevo. Aka KMCMMN or whatever.. Just wait. He should chime in and set you straight.

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I just did. He has some great info and has been very helpful.

Re:

Read the spring tech thread for sure.

I have a yj on tons with cage, fuel cell, tool box etc. Pretty sure I ended up with 170/175 springs on the rear, with 2.25" preload.

Ideal springs would have been 150/200, but I was being cheap and wanted to reuse a pair I already had, so I compromised by only ordering one pair.

My 14" c/o are set between 7 up 7 down, and 6 up 8 down at ride height.

You can install the springs you have, measure your height and do the math to figure out what springs to order, to have correct ride height with desired preload.

Or go to this link,

http://metalwerxdesign.com/files/springcalculatorv2.xlsx

and download the excel file, enter your specs, and it calculates your new desired overall rate. Then just looking the excel chart and pick the spring combo that matches the initial rate.

I created the excel file to help make spring selection easy.

It's ideal to shoot for 50 lbs different rate between the two springs, so that you can tune the height of the crossmember over rings to minimize body roll. You want the crossover rings 1-3" above the dual rate slider at ride height, with driver and passenger weight in the vehicle.

I tuned the valving for my desired ride quality and driving style.

In short:

2" preload, 50 lbs rate split between springs, x-over ring 2" above dual rate slider. Start with that and tune your valving.

Few examples of what others run.

http://www.hardlinecrawlers.com/forums/index.php?topic=39416.0

10-4.. Thanks again for all the info here. Man ya`ll are running way lighter springs than me. Thing about it it really rides good and sits good and low. I`m almost concerned that if I drop a 100 pounds on both springs its gonna sit lower than I can afford. I`m about sure this thing was originally build around 39 red labels and 43sx stickies were put on later. If it still had 39s lowering it a little wouldn`t be an issue.

Your thinking about it wrong. How much shaft is showing at ride height?

Bout 7" front and back.

truckbroke said:

Bout 7" front and back.

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How much preload? Think about it. If you have 150# spring weight to compress it 7" it will take 1050# on that one shock.
If you do the math and read the thread. The ride height will not change. Unless you want it too.

Gotcha.^^

Like others have said, the thing with running the longer springs is that you don't have to have as heavy # springs to support your rig at the same static ride height as before with the heavier and shorter springs. You will eliminate the need for helper coils and have a much better ride and a suspension that works better. The rule of thumb is the lower spring is 2" longer than shock travel, upper spring same as shock travel, so you are correct in wanting to move to 16" lower spring and 14" upper for a 14" shock. I ran 150/200 springs on the 14" Fox 2.0's on the front of my Yota with around 6" of shaft showing, you may need a tad bit more spring weight if you are running a v8 (more weight up front).

The thing about shaft showing is it's also relative to your room for uptravel. If you don't have much room for uptravel, try to set it up where it has a bit less shaft showing at static ride height... if they are set up with a lot of shaft showing at ride height and you have little room for uptravel, it's essentially wasting shock travel.

You can also check with EOR and if you order springs from them and they aren't exactly the right springrates for your application, they will usually let you send em back and swap for different ones at least once. They did when I was fooling with mine, anyways. I ran the PAC Racing springs bought from EOR - priced great and haven't read anything about them having any spring fatigue issues.

Here's what I'm running.



Fox's 2.0's on a v8 1 ton'd TJ. Had the valving changed at KOH this year and its waaaay better. 7" up and 7" down travel.


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stano said:

Here's what I'm running.

Fox's 2.0's on a v8 1 ton'd TJ. Had the valving changed at KOH this year and its waaaay better. 7" up and 7" down travel.


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What valving you running?

truckbroke said:

What valving you running?

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Not exactly sure, I had Chris from Alltech Motorsports do it. Since I'm primarily a trail rider, he put shims in for a tune in that they use as a bench mark. I know he took lots of rebound out, but couldn't tell you how much.


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