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      04-07-2020, 06:52 PM   #1
Chancef32
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Does anyone happen to know the rate of the springs want to buy them when this quarantine is over and I'm back to work but want to make sure I buy the correct ones. Also if anyone has any recommendations on any others that sounds great not sure if anyone has any experience with them and hate them.
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      04-07-2020, 07:54 PM   #2
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399lbs/in front, 565lbs/in rear. The front spring is too stiff for the rear spring included IMO. The F32 M-perf kit has the same rear spring kit, but much lower front spring rate.
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      04-08-2020, 01:12 AM   #3
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Gotcha I am looking for stiffness my floaty stock suspension has to go kind of tired of it.
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      04-08-2020, 01:13 AM   #4
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Curious why would you say the front is to stiff compared to the rear?
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      04-08-2020, 10:36 AM   #5
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Quote:
Originally Posted by Chancef32 View Post
Gotcha I am looking for stiffness my floaty stock suspension has to go kind of tired of it.
A floaty feeling is caused by being underdamped, not being undersprung.

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Originally Posted by Chancef32 View Post
Curious why would you say the front is to stiff compared to the rear?
The front is too stiff IMO because it removes flat ride, where the front frequency is lower than the rear to promote stability and fast settling of the chassis. Frequency is a function of weight and spring rate.
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      04-08-2020, 12:37 PM   #6
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Quote:
Originally Posted by FaRKle! View Post
A floaty feeling is caused by being underdamped, not being undersprung.



The front is too stiff IMO because it removes flat ride, where the front frequency is lower than the rear to promote stability and fast settling of the chassis. Frequency is a function of weight and spring rate.
Just a question, what your ideal spring rate paired with aftermarket shock like B8 and koni yellow or red. I know everyone has their own taste. But just out of curiosity this is for comfort of course.
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      04-08-2020, 01:11 PM   #7
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Not sure how everyone else does it but my friend has a spring rate of 16k on his bc coilovers got to drive it yesterday and I loved them was hoping bilstein would do the same with measurement but I dont see a spring rate any where.
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      04-08-2020, 01:28 PM   #8
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Suspension characteristics, including ride and handling, are very subjective. It's a minefield of manufacturers, specifications, prices and opinions. Thorough research is required if you want to get it 'right'.

My car is running Ohlins Road & Track : Ohlins customers 90nN/mm springs on the front (Ohlins R&T 'standard' springs are 70N) and 160N/mm on the rear.

Some people may find the ride to be too firm. That said, my wife (who drives a very softly sprung KIA Sorento) doesn't mention it.

For me the spring rates (and the damping) are excellent, but I do track my car several times each year and it's been modified as a fast road / occasional track setup.

From experience if you want decent suspension changing the dampers is a must, not just springs.
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      04-08-2020, 03:10 PM   #9
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Thats why I'm getting coilovers looking to feel more of the road
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      04-08-2020, 03:14 PM   #10
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You'll def feel more of the road with b14s. You'll also have plenty of bump steer and a "sporty" ride aka choppy and stiff. If your baseline are BCs with 16k springs, then bilsteins will prob be better than that.

Bilsteins are also monotube dampers and have a really high gas pressure. They're stiff and designed to be stiff. I ran KWs and now Bilstein on my car. The only reason I'm still running Bilsteins is because they're a donor set for my custom tuned dampers. I'm running different springs which I'll have the dampers tuned for.
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      04-08-2020, 03:24 PM   #11
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Quote:
Originally Posted by andino View Post
You'll def feel more of the road with b14s. You'll also have plenty of bump steer and a "sporty" ride aka choppy and stiff. If your baseline are BCs with 16k springs, then bilsteins will prob be better than that.

Bilsteins are also monotube dampers and have a really high gas pressure. They're stiff and designed to be stiff. I ran KWs and now Bilstein on my car. The only reason I'm still running Bilsteins is because they're a donor set for my custom tuned dampers. I'm running different springs which I'll have the dampers tuned for.

Sounds good to me I think that probably sealed the deal.
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      04-08-2020, 05:01 PM   #12
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Quote:
Originally Posted by Gen13 F36 View Post
Just a question, what your ideal spring rate paired with aftermarket shock like B8 and koni yellow or red. I know everyone has their own taste. But just out of curiosity this is for comfort of course.
This is going to depend on weight of the vehicle. For my F31, F8x ZCP front springs and stiffer (210lbs/in+) look pretty decent with the B6/8 fronts. For the B6/8 rears I would need something in excess of 1000lbs/in to bring the critical damping ratio down to not overdamped levels.
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      04-09-2020, 10:31 AM   #13
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Quote:
Originally Posted by Chancef32 View Post
Not sure how everyone else does it but my friend has a spring rate of 16k on his bc coilovers got to drive it yesterday and I loved them was hoping bilstein would do the same with measurement but I dont see a spring rate any where.
would you know if they were the stock BCs springs or the custom swift springs that can be ordered with BCs?

Last edited by brigade24; 04-09-2020 at 01:41 PM.. Reason: text quoted was incorrect
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      04-09-2020, 12:10 PM   #14
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Quote:
Originally Posted by brigade24 View Post
would you know if they were the stock BCs springs or the custom swift springs that can be ordered with BCs?
I think you're meaning to ask Chancef32. I have never used BCs on f3x.
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      04-09-2020, 01:36 PM   #15
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Quote:
Originally Posted by andino View Post
I think you're meaning to ask Chancef32. I have never used BCs on f3x.
yes you're right...sorry about that. fixed!

Last edited by brigade24; 04-09-2020 at 01:42 PM.. Reason: error correction
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      04-09-2020, 08:30 PM   #16
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If I remember they were the swift springs yes.
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      04-12-2020, 02:32 PM   #17
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Quote:
Originally Posted by Watsey View Post
Suspension characteristics, including ride and handling, are very subjective. It's a minefield of manufacturers, specifications, prices and opinions. Thorough research is required if you want to get it 'right'.

My car is running Ohlins Road & Track : Ohlins customers 90nN/mm springs on the front (Ohlins R&T 'standard' springs are 70N) and 160N/mm on the rear.

Some people may find the ride to be too firm. That said, my wife (who drives a very softly sprung KIA Sorento) doesn't mention it.

For me the spring rates (and the damping) are excellent, but I do track my car several times each year and it's been modified as a fast road / occasional track setup.

From experience if you want decent suspension changing the dampers is a must, not just springs.
Ohlins R&T are one of the best coilovers - at a price of course. I suggest the same coilovers if the budget permits.
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      04-13-2020, 09:34 PM   #18
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Loving my Fortune Auto Gen 7 series 500 with swift springs 9k ft 14k rear. Rides and handles amazing.
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      09-16-2020, 05:58 PM   #19
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Quote:
Originally Posted by FaRKle! View Post
399lbs/in front, 565lbs/in rear. The front spring is too stiff for the rear spring included IMO. The F32 M-perf kit has the same rear spring kit, but much lower front spring rate.
may i ask where did you get those numbers from?
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      09-16-2020, 07:45 PM   #20
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may i ask where did you get those numbers from?
Direct from Bilstein customer support.
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      09-17-2020, 03:45 AM   #21
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Quote:
Originally Posted by FaRKle! View Post
Direct from Bilstein customer support.
ok great thank you.
i was going to contact them!

could you comment on whether puttiing the b14 kit on my F32 440i will stop the awful pitching, especially under braking?
this is the one thing i'm trying to eliminate the most, its really bad on my car even with the Msport suspension.

i've been trying to find the spring rates of the passive Msport suspension setup to at least compare to the bilstein but can't find it anywhere.

my intention is to couple the kit with either the H&R or Eibach sway bar kit.

EDIT: i just used your excel suspension calculator and popped the figures in. It tells me that with the B14's i'd get PITCH, 2.04 Front and 1.56 rear.
So..........am i going to have to pair the rear shocks with significantly stiffer springs?

if so what rear springs will give me 1000 lbs/inch spring rate? Brands, part numbers would be super helpful.

OR.....would i be better off just going with the B12 pro kit, which consists of B8 dampers and Eibach prokit springs?
If i plug those figures into the spreadsheet it comes out with FLAT.....but presumably overall, softer setup than the B14 coilovers.

Last edited by gippy; 09-17-2020 at 04:01 AM..
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      09-17-2020, 10:51 PM   #22
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Quote:
Originally Posted by gippy View Post
ok great thank you.
i was going to contact them!

could you comment on whether puttiing the b14 kit on my F32 440i will stop the awful pitching, especially under braking?
this is the one thing i'm trying to eliminate the most, its really bad on my car even with the Msport suspension.

i've been trying to find the spring rates of the passive Msport suspension setup to at least compare to the bilstein but can't find it anywhere.

my intention is to couple the kit with either the H&R or Eibach sway bar kit.

EDIT: i just used your excel suspension calculator and popped the figures in. It tells me that with the B14's i'd get PITCH, 2.04 Front and 1.56 rear.
So..........am i going to have to pair the rear shocks with significantly stiffer springs?

if so what rear springs will give me 1000 lbs/inch spring rate? Brands, part numbers would be super helpful.

OR.....would i be better off just going with the B12 pro kit, which consists of B8 dampers and Eibach prokit springs?
If i plug those figures into the spreadsheet it comes out with FLAT.....but presumably overall, softer setup than the B14 coilovers.
I'm afraid you're asking a lot here, and it would take a not insignificant amount of effort to answer. I don't really do that for specific cases unless it's a paid consultation. My open posts and tools should give you a pretty decent idea of how things will ride or what compromises they may require.
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