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coilover spring rate and valving refrence thread

52K views 70 replies 27 participants last post by  Matti 
#1 · (Edited)
I figure start this now for the people wanting to run coil overs :D
List your:
Shocks
Length
Numbr of coils (single, dual, tri, keeper, etc)
Coil (s) length
Coil rates
number of doors
And lastly valving.

Also be subjective on if you like/don't about your handling.

This will come in handy as luckily we are running similar weight/wheelbase vehicles so provides a nice starting point for those thinking of running coilovrs (myself :thefinger: )

For those guys running a cantilever setup if you could include the ratio of your setup so we can figure the rate 1:1
:grinpimp:
 
#2 ·
Kings and Poly Performance mounts front and rear. Normally running 4" of lift height (will vary depending on what area I plan to wheel in) and 40s.

FRONT COILOVERS
12" Shocks
Dual springs: 14" compression, 12" rebound
Rate: 200 over 300

REAR COILOVERS
12" shocks for general use (have 14" shocks for the rear for special occasions too)
Dual springs: 14" compression, 12" rebound
Rate: 250 over 250

Shocks are custom valved and charged by off-road legend Richard "Goatman" Gauthier.

This set-up is fantastic for rock crawling and daily driving, but a little too spongy for Baja racing or jumping in the dunes. But having said that, it does run smoother at high speed on the dirt roads than my regular coil/shock set-up did - and the King air bumps work fantastic for playing in the dunes. I wanted my JK to own the rocks and drive smoothly to the trail, and I achieved that goal. If I lived in an area where most wheeling is dirt roads and mud, Id go with higher rate springs.

Land vehicle Vehicle Car Automotive tire Tire
 
#7 · (Edited)
a cantilever setup will be a ratio that is not true 1:1, ie for each in of travel at wheel an inch travel at shock. This also applies to shocks in front of the axle centerline but still on the axle tube but not enough to be a concern for our application.

For example a shock mounted 1/2 way on a lower (middle) would see 1/2" travel for every inch of wheel travel. this would also double the force on the spring and valve. Same with a fancy cantilever setup that uses a free arm and links. So if you were using a 300lb spring on the tube it would require a 600lb spring on the halfway point of a control link. Your valves would also be working twice as hard because it would be dampening 1inch in 1/2 inch of movement.

Simple lever principle.

A similar thing also applies to shocks mounted at a severe angle, but one again not really applicable to our application.


Oh ya, mention if you are 4dr or 2dr in your specs :laughing:
 
#4 ·
4dr about 6 1/2" lift 14" fox coilovers front and rear. Front tribe mounts running 250 over 425
Rear 200 over 500 custom mounts floats on 40s rides like a cadilac. Wouldn't change anything


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#6 · (Edited)
12 inch fox 2.0 dual rate front and rear with Tribe 4x4 mounts and Poly rear mounts.

Springs rates

Front 500lb 10inch over 450 12 inch
Rear 500lb 10 inch over 250 12 inch





Rear install write up

Front Tribe 4x4 write up


Im my opinion these are not the ideal spring rates for the rocks. Im going to be going to 350/250 and out back 300/200

On the road handling is amazing. the Jeep has great offroad manners as well but i feel like im losing some uptravel do to a heavy top spring.


I wanted to stay right around 4.5 inches of lift with the current springs im right at 4 inches of lift



 
#10 ·
Fox 16" remote Res front and rear, 2 door, 112"WB, 5300lbs
Front - Tender up top, 14" 200lb spring, 16" 300lb spring, .015 flutter with a .010 on rebound.
Rear - Tender, 14" 175lb spring, 16" 250 lb spring, .015 flutter valving with a .010 stack on the rebound side

Also doing coilovers in the front of a 4 door in about a month. It will run Fox 12" emulsion coilovers with 200/300 springs, base valving at 40/40 with 2.0 triple bypasses. I have to mess with that valving upon install but I'll let you know when it happens.

Bypass valving is 90/50
 
#13 ·
Help

I have 14" SAW coilovers w/resi. Yet to install because I have no understanding. Can someone please give me a jump start? They are set up for dual rate. What length of springs and compression? :mr-t:JKU, weighs about 4800 lbs. I dont drive it much because I have a work vehicle. I would like it to run smooth on the road and then tackle climbs and some minor to medium rocks. Any information would be a great help. Will be running Tribe 4x4 front and Rebel Offroad rear thru the tub. Thanks in advance for information to set this up.:mr-t:
 
#14 ·
I have 14" SAW coilovers w/resi. Yet to install because I have no understanding. Can someone please give me a jump start? They are set up for dual rate. What length of springs and compression? :mr-t:JKU, weighs about 4800 lbs. I dont drive it much because I have a work vehicle. I would like it to run smooth on the road and then tackle climbs and some minor to medium rocks. Any information would be a great help. Will be running Tribe 4x4 front and Rebel Offroad rear thru the tub. Thanks in advance for information to set this up.:mr-t:

lets start :D
1) depends on what you plan to do with it will dictate rate and valving. the dual rate is basically when the first (lighter lb) spring reaches its max compression in either LB or when touching itself then the next (higher) lb spring takes effect. it is progressive instead of linear, you just need to figure what you want your ride to be like first.
You would want a main (lower) that is 2" or so LONGER than your travel and an upper that is 2" or so less.

Then read and ask here or Pirate4x4's thread dedicated to shock tuning or contact a reputable company (Poly Performance, Fox, FOA have all been VERY helpful in assisting people with tuning shocks)

2) put your JKU on a scale, I think you are a couple hundred pounds shy of what its curb weight is :laughing:
 
#16 ·
Top is the tender which is the light one, main spring on bottom is the heavy weight spring. But it only really matters if you are using the adjuster, to limit how far the tender can compress


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#17 ·
I found an interesting formula to tell you spring rates if you dont know what yours are and they dont have any markings on them. All you need is a caliper that measures in mm and some math skills.


(wirediameter^4*80400)/(8*ccdia^3*number of active coils)

This gives you the result in N/mm

ccdia = center to center diameter. 2.0 coilover springs are 2.5" (63.49999999993142 mm)

To get lbs/in multiply your answer by 5.71014716277 (1 N/mm = 5.71014716277 lbs/in)



Anyone with known coil rates want to test this out and see how accurate the formula is? :grinpimp::beer:
 
#20 ·
Another thing to remember is the more angle on the Coilover the larger the spring rates will be, so when you pick your setup find someone running the same setup before you start buying the coils


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#27 ·
Alot depends on who's Coilover setup your running on rear. More of an angle of the Coilover will require higher spring rates


I'm willing to die to protect my 2nd amendment rights, are you willing to die trying to take them away?
 
#29 ·
If you can mount them about angled at about 10 degrees out towards the tires to gain a little more roll stability. Spring rates will depend on how the shock will sit at ride height and how much travel you have planned for them. How much lift you want to run?
Do you have the front and rear weights for your rig - axles and tires?
 
#30 ·
Very interested in this. I hope to run front 14" coilovers with 3-3.5" of lift. Seem possible? My thought is to make the upper mounts as high as possible, and build lower mounts that sit an inch below the axle. I know it loses some ground clearance, but they would still be higher that my control arm mounts. This is on a two door. My thoughts were medium valving with 250 over 300 springs.
 
#32 · (Edited)
This is totally doable on the rear like u mentioned, mount the towers high as possible. Just be ready to change out springs to get the right lengths for your ride height.

I'm using 250/300 on the rear at the moment. Supposedly shocks are valved 40/70. With a 39.5 spare on i was getting severe rear body roll in turns. Removed the spare and it took away most of it but I could just tell by feel that the valving was way to soft. I'm getting them firmed up as we speak.

With my ride height & up travel and such I'm having to swap out my lower 12" coils to 14" if not I would need a helper coil and I think that's just a half ass fix for the issue. And maybe the cool factor of running tripple rate. Truth be told its just a helper 40lbs isn't much but to keep the spring seated.

Coilover really are the shit when it comes to ride quality on and off road but tuning them can be a pita.

sent from tapatalk on GS3
 
#31 ·
If you are going to run a 3-3.5" lift with that heavy a spring rate you would need to run a triple rate with a short secondary coil and a tender coil.
Do you know what your up travel will be?
You are going full hydraulic right?
 
#36 ·
I didn't realize there was a cool factor for running a triple rate. The third coils is just there to take up space and has absolutely nothing to do with ride. It just keeps the coils from unseating from full extension. You typically need them if you are running a heavy coil rate and a lcog build with limited up travel.
 
#40 ·
The 14" coilovers I have for the rear of my 2 door have 14" 250 over 14" 350 springs and F15 flutter valving and 10 PO4810 rebound valving (King Specs). I was told this should work well for my needs. I still need to do some learning to about valving. Can anybody direct me to some good reading about coilover valving or just give the quick and dirty explanation?

I haven't installed them yet (still a couple months out from doing my stretch). I will be sure to update the thread with the final spring rates that I go with.
 
#42 ·
I would agree with chad, I am running a drag link flip with 4" of lift and only have 2" of up travel up front. With your notch and 3.5" of lift I would think you will be hard pressed to get 4" of up travel.
 
#44 ·
You can still run a 14" coil over with that set up, you will however have to run a light coil rate or run a shorter top coil with a tender coil so you keep you coils in contact for the limited up travel.
 
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