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Coilover rates for Unibody rigs: POST UP YOUR SPRING RATES!

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#21 ·
ashmanjeepXJ said:
How is the rear weight supported? Is it level?

You have a 136.4lb/in rate combo.
How much do the coils compress?

Measure those inches and multiply by 136.4 and you know your weight.

Once you know the weight and know the height you want you can pick coils.
Click to expand...
ok today marks the official day my jeep sat down on its own weight.

it's sitting on level ground with single rates front and rear (for testing)

front - 16" 300's
COMPRESSED at 13 7/8"

rear - 16" 250's
COMPRESSED at 13 7/8"

for ride height I want 5" of shaft showing on the coilover.

:D
 
#22 ·
BacklashXJ said:
ok today marks the official day my jeep sat down on its own weight.

it's sitting on level ground with single rates front and rear (for testing)

front - 16" 300's
COMPRESSED at 13 7/8"

rear - 16" 250's
COMPRESSED at 13 7/8"

for ride height I want 5" of shaft showing on the coilover.

:D
Click to expand...
Your front is 675Lbs per corner
Your Rear is 560Lbs per corner

16in shocks?
Front
11in of compression you want a 61.4lbs combined rate.
A 100lb 16in over a 150lb 16in spring would get you to 60lb rate

Rear
16in shock 11in of compression
50lb combined rate
100/100 coils give you 50lb rate

14in shock...5in up
front 150/150
Rear 100/150
 
#23 ·
for a full body rig, does that seem too mushy?

i'm also going to assume that that's 14" top coils, 16" bottom coils?

if the case is that it's too mushy, would getting stiffer lower coils and then adjusting the top up 5" and getting a 5" tender work? or is that not worth it?

thanks man, this info is awesome!
 
#24 ·
What about preload Ashman? According to the 11 pages I just read (which I'm still digesting) he wants 2-3" of preload. With those rates and that much preload he wouldn't he sit about 2 inches or so too high?
 
#27 ·
I'm running 12x2.5 FOA Remote Resi C/O on my Full bodied XJ with stock 4.0L. I went with 12x3x275 over 14x3x300 PAC springs. 150psi of nitrogen. With Firm compression and Firm rebound vavling, it still feels pretty soft when "going fast".

Here is how much shock shaft is showing.

Image
 
#28 ·
RDK_YJ88 said:
I'm running 12x2.5 FOA Remote Resi C/O on my Full bodied XJ with stock 4.0L. I went with 12x3x275 over 14x3x300 PAC springs. 150psi of nitrogen. With Firm compression and Firm rebound vavling, it still feels pretty soft when "going fast".

Here is how much shock shaft is showing.

Image
Click to expand...
Posts like this make me not so convinced of the theories in the thread linked by Ashmam earlier. That being said, if you feel you are too soft mainly when going
Fast; it sounds like you need more compression valving. What are you running now?
 
#29 ·
BacklashXJ said:
for a full body rig, does that seem too mushy?

i'm also going to assume that that's 14" top coils, 16" bottom coils?
Click to expand...
On a 16in CO I would run a 16in over a 16in with a keeper.

The rates I gave you would give you minimal preload so you should run a keeper. adding weight will get you more pre load. same springs. I dont know how much your bumper weighs.... do the same test with all the weght... motor installed that kinda stuff...:flipoff2::shaking:

If its too mushy, add valving, and move the slider stop down.

If you run a 16/16 you can run the stiff spring on the top or bottom to give you more options for the dual rate slider stop.

Some shocks have shorter bodies and may not fit a keeper and two 16s on a 16in shocks. measure your shock body before ordering coils. It would fit on ADS shocks.
 
#30 ·
I just picked up my shocks yesterday, 16" Fox 2.0. My XJ's getting a full cage, and the front bumper weighs about 75 lbs, plus a winch.

I've got one guy telling me 300/400 springs minimum, but I'm not seeing anybody else on here running that heavy. I'd like to avoid running a keeper spring, so I was thinking one 16" and one 18" spring. Looking at PAC springs.

This is my first set of coilovers, so I'm looking for suggestions.
 
#33 ·
FST said:
Posts like this make me not so convinced of the theories in the thread linked by Ashmam earlier. That being said, if you feel you are too soft mainly when going
Fast; it sounds like you need more compression valving. What are you running now?
Click to expand...


I'm planning on re-valving them, but probably not until after winter. I bought the shocks used and was told they were Firm compression and Firm rebound, I haven't pulled the shocks apart and measured the shims yet.
 
#34 · (Edited)
for people running foas... how firm is their firm valving?

im going to order a set when i find a front 60, no winch and a small front bumper so not a lot of weight up front. im looking for something to ride smooth yet remain stable on the road to and from the trail. i know spring rate has a lot to do with it but some feed back would be nice:smokin:

second newb question... when choosing a rebound rate, a firm rebound rate means that it will keep the shock from rebounding too fast correct? or is it the other way around?
thanks

/newbish questions rant:homer:
 
#35 ·
sandaddik2 said:
im looking for something to ride smooth yet remain stable on the road to and from the trail. i know spring rate has a lot to do with it

a firm rebound rate means that it will keep the shock from rebounding too fast
Click to expand...
To control body Roll having the slider stop low so the second rate comes in early does help, but Coilover valving changes can really fight body roll and maintain a soft ride.

Correct, more rebound prevents the shock from extending quickly, if you have to much rebound it will give you a stiff ride, on repeated bumps the shock will pack in.. Each hit the shaft pushes in but with too much rebound it stays in for the next hit and can float around full bump.

More rebound does fight body roll.
 
#37 ·
sandaddik2 said:
for people running foas... how firm is their firm valving?

im going to order a set when i find a front 60, no winch and a small front bumper so not a lot of weight up front. im looking for something to ride smooth yet remain stable on the road to and from the trail. i know spring rate has a lot to do with it but some feed back would be nice:smokin:

second newb question... when choosing a rebound rate, a firm rebound rate means that it will keep the shock from rebounding too fast correct? or is it the other way around?
thanks

/newbish questions rant:homer:
Click to expand...
FOA's are fairly light with valving, I have a firm/med set and now im running med/med and like the med/med better, shit rides like a Caddy on the bypasses - but im running the 16" with 250(14)/200(16) --- i need to go softer and use a lighter sping on top...
 
#38 ·
BacklashXJ said:
hey Ashman, you said 16 uppers, 16 lowers, what would it be with 14 uppers? .5 - 1" preload on the adjuster (with keeper coil of nessisary).

thanks!
Click to expand...
14/16 or 16/16 would be the same rates, same preload, the coil adjuster will be in different positions but same amount of pre load.
If you can fit a 4in keeper 16in 16in I would do that.
 
#39 · (Edited)
ashmanjeepXJ said:
14/16 or 16/16 would be the same rates, same preload, the coil adjuster will be in different positions but same amount of pre load.
If you can fit a 4in keeper 16in 16in I would do that.
Click to expand...
gotcha. with the higher rates that were on there, i had the adjuster all the way up, so obviously it would need like a 8" keeper spring... with the new rates and 14" over 16", do you think i would even need a keeper coil?

EDIT: sorry i'm asking so many questions, i've just heard some people say 250/300 would be too light, and i'd need to limit strap it, others say 200/250 with keeper coils... now you did the math and it's 100/150...
 
#40 ·
DRICH394 said:
FOA's are fairly light with valving, I have a firm/med set and now im running med/med and like the med/med better, shit rides like a Caddy on the bypasses - but im running the 16" with 250(14)/200(16) --- i need to go softer and use a lighter sping on top...
Click to expand...
sounds like a good starting point... do you run your rig on the street at all?
as much as a linked rig on 42s would run on the street :laughing:
 
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