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Old Aug 21, 2011 | 11:13 PM
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Default Spring rate

I'm looking to upgrade my springs to a stiffer rate. I'm currently running a 12k/5k oem style coilover setup. Any advice on what rates to try to get? I was thinking like 14/12? Thanks
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Old Aug 22, 2011 | 02:03 AM
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Originally Posted by acke15
I'm looking to upgrade my springs to a stiffer rate. I'm currently running a 12k/5k oem style coilover setup. Any advice on what rates to try to get? I was thinking like 14/12? Thanks
I'm running 12/10 but it really depends on a lot of things, Tires, driving style, etc... 14/12 is a little stiff IMO but I know many people that run that setup and like it.
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Old Aug 22, 2011 | 10:13 AM
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Originally Posted by Lightning Guy
I'm running 12/10 but it really depends on a lot of things, Tires, driving style, etc... 14/12 is a little stiff IMO but I know many people that run that setup and like it.
Tires will be r-s3's. I have my coils set to a stiffer setting. I like it stiffer than most.
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Old Aug 22, 2011 | 11:47 AM
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12/5 in the oem style? Maybe you meant 12/5 in the "true coilover style". Otherwise 5 in the rear is softer than stock. If you are refering to 5kg on the shock thats about the average spring rate for mosts setups on the rear and and may be a little soft in comparison to the front spring. I don't remember the exact ratio but I think its .67 and that would suggest a spring in the 7kg range on the shock would be a similar setup to the 12/10 I and Lightning Guy run.

What type of coilovers are you running?

Last edited by Zazz93; Aug 22, 2011 at 11:49 AM.
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Old Aug 22, 2011 | 02:31 PM
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12/5 with true rear is almost identical to 12/10 OEM style. I run 12.4 front 5k rear right now. Depending on your entire setup you may be able to get away with a stiffer spring. The biggest factor will actually be your shock, followed by alignment (that running your current tires)

BTW what size are the tires?
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Old Aug 22, 2011 | 05:22 PM
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Stance coilovers. (ya I know). The tires are 285/35/18 f and r
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Old Aug 22, 2011 | 05:25 PM
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I misread, the coils I have are a oem style coilover. With 12kF/11kR.
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Old Aug 22, 2011 | 05:27 PM
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Originally Posted by terrasmak
12/5 with true rear is almost identical to 12/10 OEM style. I run 12.4 front 5k rear right now. Depending on your entire setup you may be able to get away with a stiffer spring. The biggest factor will actually be your shock, followed by alignment (that running your current tires)

BTW what size are the tires?
That ratio is more than double?

Last edited by Zazz93; Aug 22, 2011 at 05:40 PM.
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Old Aug 22, 2011 | 05:39 PM
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Originally Posted by acke15
I misread, the coils I have are a oem style coilover. With 12kF/11kR.
That's pretty aggressive, but if you want more... I guess. What is the car doing that you don't like?
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Old Aug 22, 2011 | 06:53 PM
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Originally Posted by Zazz93
That ratio is more than double?
The motion rates are:
Front .688

Rear in oem location .649

Rear when on damper body .97

How the math is used to calculate wheel rates
690/690 rate setup, rear's in oem location

Front
690 x .688 = 474.72 x .688 = 326.60 rounded to 327 and you have your front wheel rate

Rear
690 x .649 = 447.81 x .649 = 290.62 rounded to 291 and you have your rear wheel rate


^ replace the .649 number with .97 for calculating the wheel rate on a truecoilover rear setup.
Here is what i go off of
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Old Aug 22, 2011 | 10:18 PM
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Originally Posted by Zazz93
That's pretty aggressive, but if you want more... I guess. What is the car doing that you don't like?
The rear end hops some times when I turn hard
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Old Aug 23, 2011 | 08:03 AM
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Originally Posted by acke15
The rear end hops some times when I turn hard
How low is your car? Could be a lot of things causing that, first thing i would look at is ride height.
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Old Aug 23, 2011 | 08:44 AM
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Quick question- Is the surface fairly smooth, moderate or rough?

Things I would look at for that problem:

-Too low - This refers to you being on the bumpstops effectively increasing the spring rate
-Too much rebound dialed-in - This would cause the suspension to not hold the road's contours
-Bad shock
-Bad bushing
-Too much spring rate

So its likely more spring rate is only going to make this worse. Remember stiffer is not always better. Rule of thumb, run it as stiff as you can while keeping the suspension moving and working. When the wheel is hopping around generally you want softer settings to keep the tire in contact with the ground. The exception to this is when there is too little rebound and the wheel is boucing around with no dampening but this exception is more likely a broken shock.

Last edited by Zazz93; Aug 23, 2011 at 08:50 AM.
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Old Aug 23, 2011 | 09:04 AM
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spring rates are generally the last thing to change unless you've got a lot of data to back up the change that you're making

the problem likely lies elsewhere

setting dampers to a stiff setting in the first place could be part of the issue, as can ride height as mentioned, as can a poorly valved (or blown) damper.
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Old Aug 23, 2011 | 03:19 PM
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I'm pretty low. That is prolly what is causing it.
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Old Aug 23, 2011 | 04:59 PM
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you may want to also soften up your sway bars.


I generally don't go any lower than setting my half axles level to the ground. just my setup.
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Old Aug 23, 2011 | 05:40 PM
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Originally Posted by Lightning Guy
you may want to also soften up your sway bars.


I generally don't go any lower than setting my half axles level to the ground. just my setup.
I have stock sways. I'll be getting hotchkis this winter
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Old Aug 23, 2011 | 06:03 PM
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Originally Posted by acke15
I have stock sways. I'll be getting hotchkis this winter
I'm thinking about going back to the stock rear bar, the hotchkis is too stiff for my liking and my setup.
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Old Aug 23, 2011 | 06:10 PM
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Originally Posted by acke15
I have stock sways. I'll be getting hotchkis this winter
Post pics of the car, as you said its probably way to low. BTW do you have a proper diff?
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Old Aug 23, 2011 | 06:40 PM
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I don't think the sways would cause rear hopping Lightning Guy. They may create more roll resistance than needed with an 11k spring, but unlikely to create wheel hop/chatter. I run a 12/10k set-up with Hotchkis bars and think its a little aggressive if I'm aggressive with my inputs otherwise its pretty docile.

+1 on the pics for ride height.

Last edited by Zazz93; Aug 23, 2011 at 06:42 PM.
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