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BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > Technical Forums > Suspension | Chassis | Brakes > F3x Chassis Suspension Frequency Calculator, By FCM & FaRKle!
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      06-01-2020, 03:43 PM   #23
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Quote:
Originally Posted by Gen13 F36 View Post
I'm not saying the numbers 100% the same with xdrive and my RWD F36. I think the front /rear weight bias contributes to the unusually closed numbers for a flat ride setup. There are still difference.

I could be wrong with my argument. Anyway I'll try to get a 4k/12k spring rate for mine but it will be awhile when I'm going to replace my suspension, probably end of this year or early next year.
ok kool.

I plugged my numbers in under the custom setting and the range of spring rates that can be used to meet the flat ride threshold is substantial.
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      07-14-2020, 02:41 PM   #24
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I just got the spring rates for my ST suspension springs for ActiveHybrid f30, they say 23N/mm front, 27N/mm rear (130 and 154 lbs/in) seems far off from what you have for other models...

i can't run the calculator off my ipad now but what do you make of these? Makes sense considering the 50/50 weight distribution?
I asked eibach spring rates for AH3 to compare, no answer yet.

Thanks!
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      07-14-2020, 02:54 PM   #25
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Quote:
Originally Posted by Lancelot View Post
I just got the spring rates for my ST suspension springs for ActiveHybrid f30, they say 23N/mm front, 27N/mm rear (130 and 154 lbs/in) seems far off from what you have for other models...

i can't run the calculator off my ipad now but what do you make of these? Makes sense considering the 50/50 weight distribution?
I asked eibach spring rates for AH3 to compare, no answer yet.

Thanks!
The OE front spring rate for the AH3 could be 23N/mm, but if the ST coilovers are stiffer than OE they're probably much higher than that. There's absolutely no way the rear spring would only be 27N/mm stock or ST due to how inboard the spring is on the arm. Is it possible they were quoting the rear 27N/mm as the wheel rate? I'd again be very surprised if the rear wheel rate on the ST coilover setup was that low since some of the OE BMW suspensions are stiffer than that.
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      07-15-2020, 06:46 AM   #26
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Quote:
Originally Posted by FaRKle! View Post
Quote:
Originally Posted by Lancelot View Post
I just got the spring rates for my ST suspension springs for ActiveHybrid f30, they say 23N/mm front, 27N/mm rear (130 and 154 lbs/in) seems far off from what you have for other models...

i can't run the calculator off my ipad now but what do you make of these? Makes sense considering the 50/50 weight distribution?
I asked eibach spring rates for AH3 to compare, no answer yet.

Thanks!
The OE front spring rate for the AH3 could be 23N/mm, but if the ST coilovers are stiffer than OE they're probably much higher than that. There's absolutely no way the rear spring would only be 27N/mm stock or ST due to how inboard the spring is on the arm. Is it possible they were quoting the rear 27N/mm as the wheel rate? I'd again be very surprised if the rear wheel rate on the ST coilover setup was that low since some of the OE BMW suspensions are stiffer than that.
I agree!

Still, KW confirmed 23 n/mm front - 27n/mm rear, considering the brevity of their answer i didn't get much more... could be at wheel indeed.

Eibach (Germany) responded but declined to provide spring rates, they consider this is confidential info.

not so easy to compare products!
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      07-16-2020, 12:29 AM   #27
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Quote:
Originally Posted by Lancelot View Post
I agree!

Still, KW confirmed 23 n/mm front - 27n/mm rear, considering the brevity of their answer i didn't get much more... could be at wheel indeed.

Eibach (Germany) responded but declined to provide spring rates, they consider this is confidential info.

not so easy to compare products!
I took a look at the ETK system and AH3 OE springs seem to be the same as the F34 4cyl xDrive ones. The base suspension front spring is actually a bit stiffer than 23N/mm, and the M-Sport/Adaptive-M suspension springs are certainly stiffer.

As far as Eibach goes, the AH3 kit is E10-20-031-05-22 with spring rates 34N/mm front and 95N/mm rear.

Last edited by FaRKle!; 07-16-2020 at 12:36 AM..
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      07-16-2020, 01:21 AM   #28
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Quote:
Originally Posted by FaRKle! View Post
Quote:
Originally Posted by Lancelot View Post
I agree!

Still, KW confirmed 23 n/mm front - 27n/mm rear, considering the brevity of their answer i didn't get much more... could be at wheel indeed.

Eibach (Germany) responded but declined to provide spring rates, they consider this is confidential info.

not so easy to compare products!
I took a look at the ETK system and AH3 OE springs seem to be the same as the F34 4cyl xDrive ones. The base suspension front spring is actually a bit stiffer than 23N/mm, and the M-Sport/Adaptive-M suspension springs are certainly stiffer.

As far as Eibach goes, the AH3 kit is E10-20-031-05-22 with spring rates 34N/mm front and 95N/mm rear.
Thanks! Great info
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      07-22-2020, 11:05 AM   #29
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Quote:
Originally Posted by Logicoeur View Post
So if you get stiffer springs in the rear on any of the BC, or FA and the like, are you really doing yourself any benefit if the shock isn't valved to match?
They are usually re-valved to match and they provide a shock dyno (I believe FA does)
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      09-01-2020, 04:52 PM   #30
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For those with F30 335i RWD, what spring rates are you guys running? In particular, the HPDE guys.
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      09-02-2020, 10:10 AM   #31
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Am I missing something, the download link isn't working for me?

Looking at the Fortune Auto 500 series with swift springs at 5k / 16k as per Farkles recommendation on another thread. Has someone already plugged these numbers in?

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      09-02-2020, 10:16 AM   #32
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Originally Posted by pauli18c View Post
Am I missing something, the download link isn't working for me?

Looking at the Fortune Auto 500 series with swift springs at 5k / 16k as per Farkles recommendation on another thread. Has someone already plugged these numbers in?

2017 340i rwd
Works fine for me. I just clicked on the link and the download window appeared.
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      09-02-2020, 10:25 AM   #33
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Link works for me as well. Now I just gotta watch the video to learn how to use it.

FaRKle! , do you remember which thread it was that you recommended spring rates?
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      09-02-2020, 11:40 AM   #34
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I'm a dummy, I thought the link was taking us to Fat Cat's website. When I clicked it, it was flashing the screen but didnt realize it was actually downloading it in my downloads folder. So I have about 6 copies now

Looks like those rates work
Name:  Capture.JPG
Views: 114
Size:  141.7 KB


itsrichierich , this was the thread I was referring to
https://f30.bimmerpost.com/forums/sh....php?t=1668220
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      09-02-2020, 12:15 PM   #35
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Quote:
Originally Posted by pauli18c View Post
I'm a dummy, I thought the link was taking us to Fat Cat's website. When I clicked it, it was flashing the screen but didnt realize it was actually downloading it in my downloads folder. So I have about 6 copies now

Looks like those rates work
Attachment 2404041


itsrichierich , this was the thread I was referring to
https://f30.bimmerpost.com/forums/sh....php?t=1668220
Thank buddy
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      09-06-2020, 09:07 AM   #36
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this calculator is great! definitely a new found understanding on spring rates for me. thanks FaRKle!

pauli18c I'm interested in the 500 series FA coils too with swift springs like FaRKle! suggest at 5k/16k. I wonder what FA has to say about that setup.
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      09-16-2020, 05:26 PM   #37
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Not sure if anyone noticed, but when downloading the file on a computer, it doesn't show the vehicle's weight and etc. But when downloading on a phone, it shows that information.
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      09-17-2020, 06:44 AM   #38
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Quote:
Originally Posted by R32DBP View Post
this calculator is great! definitely a new found understanding on spring rates for me. thanks FaRKle!

pauli18c I'm interested in the 500 series FA coils too with swift springs like FaRKle! suggest at 5k/16k. I wonder what FA has to say about that setup.
I posted their response in the other FA 500 thread

https://f30.bimmerpost.com/forums/sh....php?t=1668220
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