Ok need some help figuring my spring rates. 14" 2.0 coilover. Running 14" 150 over 16" 250. Zero preload top spring is compressed 4" lower is compressed 2.5". Showing bout 7" of shock shaft. Would like to drop it another 3". So the question is. Whats the best way to do this.?? Never mess with coilovers b4. Running them in the front of a yj stretched and 4.0. Any help would be great.
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Help Support Hardline Crawlers :
coilover help
- Thread starter screamn56
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waggener1
Well-Known Member
In order to calculate your effective spring rate (the rate of the two springs combined), you should use k = (k1 x k2) / (k1 + k2).
So.... (150 x 250) / (150 + 250) = 93.75 lbs/in. So call it 94 lbs/in.
Use F = kx (Force = spring rate times displacement) to get a good idea of your unsprung weight on a given corner. If your shocks are angled, this gets a little more complicated. Anyway, this should get you fairly close.
F = 94 lbs/in x 6.5 in
F = 611 lbs
Knowing this, you can play with the numbers to determine a spring rate that will give you the ride height your after.
So.... (150 x 250) / (150 + 250) = 93.75 lbs/in. So call it 94 lbs/in.
Use F = kx (Force = spring rate times displacement) to get a good idea of your unsprung weight on a given corner. If your shocks are angled, this gets a little more complicated. Anyway, this should get you fairly close.
F = 94 lbs/in x 6.5 in
F = 611 lbs
Knowing this, you can play with the numbers to determine a spring rate that will give you the ride height your after.
waggener1
Well-Known Member
Yes, assuming your shocks are mounted vertical. Once you introduce angle into the setup, trig functions come into play. Provided your shocks aren't angled too much, you should be able to get close without getting too deep into the math. I hope this will be helpful.
waggener1
Well-Known Member
The correct answer is ....... It all depends. There are a number of factors to take into consideration, shock travel, individual spring rates, combined spring rate, stop collar location (tender spring lockout), the angle that the shock is mounted, and the list goes on. You could even bring conservation of mechanical energy into the picture. I'm certainly not an expert, nor do I claim to be one. Pirate 4x4 has the most comprehensive article (that I've found) concerning this topic. I would encourage you to take a look at "The Coilover Bible" articles written by Bill Ansell. There's a tremendous amount of information there.
The quick and dirty answer....... I've heard some say, run a main spring length equal to your shock travel and a tender spring length two inches shorter than the main.
The quick and dirty answer....... I've heard some say, run a main spring length equal to your shock travel and a tender spring length two inches shorter than the main.
TacomaJD
I LIKE CHEAP STUFF.....
waggener1 said:
Main spring 2" longer than shock travel and upper (tender spring) the same length as shock travel has been the going fad these days from what I've been reading. (although I believe there isn't one single "right" answer to that)
Nuts
Well-Known Member
So then a 16" shock would use a 18" and a 16" spring?TacomaJD said:
Neal3000
Well-Known Member
AdamF said:
Thats what the flatbiller shock god says to do
Neal3000
Well-Known Member
pachary said:
Quit using shitty springs, cheap fawker
TacomaJD
I LIKE CHEAP STUFF.....
Re: Re: Re: coilover help
And aside from reading that in numerous places, that's the way Jimmy Penner set up my coilovers. (14" travel, 16" lower and 14" upper). So I figure if that's the way he does it, then bygawd it's right! Haha.
Those sizes actually fit good on the shock, especially after preloading. After I put the springs on the shock, there were still plenty threads to get the spanner nuts started and run down about an inch before meeting the top spring, so they aren't "too long". Unless I'm wrong, this setup will prevent those that you see with like 5-6"+ of threads showing above top spring once preloaded accordingly, allowing full use of the shock the way it's intended (provided spring rates are correct).
I think most people use too short of springs and go too heavy on spring rates, where as using longer springs, and a little lighter spring rates, and preloaded properly, you get optimal performance due to the progressional spring rates that come after properly preloaded.
I'm still green in the world of coilovers so I may be terribly wrong with that theory, if so, please inform me why, because I like learning...especially if my train of thought is incorrect.
Neal3000 said:
And aside from reading that in numerous places, that's the way Jimmy Penner set up my coilovers. (14" travel, 16" lower and 14" upper). So I figure if that's the way he does it, then bygawd it's right! Haha.
Those sizes actually fit good on the shock, especially after preloading. After I put the springs on the shock, there were still plenty threads to get the spanner nuts started and run down about an inch before meeting the top spring, so they aren't "too long". Unless I'm wrong, this setup will prevent those that you see with like 5-6"+ of threads showing above top spring once preloaded accordingly, allowing full use of the shock the way it's intended (provided spring rates are correct).
I think most people use too short of springs and go too heavy on spring rates, where as using longer springs, and a little lighter spring rates, and preloaded properly, you get optimal performance due to the progressional spring rates that come after properly preloaded.
I'm still green in the world of coilovers so I may be terribly wrong with that theory, if so, please inform me why, because I like learning...especially if my train of thought is incorrect.
Neal3000
Well-Known Member
pachary said:
i don't disagree with you at all about the quality of those shocks or the way you got treated.........i guess like a lot of places, you have to careful what you buy from where you know? you don't go to harbor freight to get your welder and plasma cutter, but other things they have are fine for a great price.
Neal3000
Well-Known Member
Re: Re: Re: coilover help
i think you are right on target, a lot of people tune their ride with springs instead of revalving, and get heavy springs to keep from bottoming out. what spring rates did you go go with again? i'm about ready to get lighter springs and retune mine
TacomaJD said:
i think you are right on target, a lot of people tune their ride with springs instead of revalving, and get heavy springs to keep from bottoming out. what spring rates did you go go with again? i'm about ready to get lighter springs and retune mine
TacomaJD
I LIKE CHEAP STUFF.....
Re: Re: Re: Re: Re: coilover help
Valving says 50/70 on shocks and spring rates are 100/200 PAC Racing Springs. I picked up some spanner wrenches from my buddy today, I have to play with the dual rate stop ring and adjust preload. It is basically sitting on the heavy spring only now at static ride height, because the dr stop ring is ran down against the slider. I'm gonna back it off and try to set it where it hits the main spring just before the tire gets into what's left of the fender on uptravel. Then I imagine I'll have to add way more preload to get back to ride height/fix body roll.
So technically, my spring rates may not be perfect, I'll have to play with it first and see what happens when I back the stop ring off. Riding on the heavy spring all the time is definitely why there is zero body roll, but it rides too stiff. Maybe I can adjust it and find a happy medium where it rides good, limits uptravel at the right point without hitting bump stop hard, and stays stable.
Regardless, it is 100 times better now than it was with leafs and will only get better from here the more I fool with it.
Neal3000 said:i think you are right on target, a lot of people tune their ride with springs instead of revalving, and get heavy springs to keep from bottoming out. what spring rates did you go go with again? i'm about ready to get lighter springs and retune mine
Valving says 50/70 on shocks and spring rates are 100/200 PAC Racing Springs. I picked up some spanner wrenches from my buddy today, I have to play with the dual rate stop ring and adjust preload. It is basically sitting on the heavy spring only now at static ride height, because the dr stop ring is ran down against the slider. I'm gonna back it off and try to set it where it hits the main spring just before the tire gets into what's left of the fender on uptravel. Then I imagine I'll have to add way more preload to get back to ride height/fix body roll.
So technically, my spring rates may not be perfect, I'll have to play with it first and see what happens when I back the stop ring off. Riding on the heavy spring all the time is definitely why there is zero body roll, but it rides too stiff. Maybe I can adjust it and find a happy medium where it rides good, limits uptravel at the right point without hitting bump stop hard, and stays stable.
Regardless, it is 100 times better now than it was with leafs and will only get better from here the more I fool with it.
TacomaJD
I LIKE CHEAP STUFF.....
Re: Re: coilover help
Well, done some adjusting. Moved the dual rate stop ring way up and of course ride height dropped to where the dual rate slider hit the stop even with it set way high. Spanner nuts were only about an inch down from top of the threads, so I tightened them down another 1.5" and now the dual rate slider is OFF of the stop ring, so it is riding on the 100# top spring also now. But front ride height is still a tad lower than rear. Hopefully I can tighten em down another inch or so and that even out the ride height.
Here is a pic of how they look now. And sorry for the thread jack.
Well, done some adjusting. Moved the dual rate stop ring way up and of course ride height dropped to where the dual rate slider hit the stop even with it set way high. Spanner nuts were only about an inch down from top of the threads, so I tightened them down another 1.5" and now the dual rate slider is OFF of the stop ring, so it is riding on the 100# top spring also now. But front ride height is still a tad lower than rear. Hopefully I can tighten em down another inch or so and that even out the ride height.
Here is a pic of how they look now. And sorry for the thread jack.
