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      08-04-2020, 08:50 PM   #1
Juice247
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'17 440xi GC want to sharpen steering/suspension

I absolutely love my 440, but the steering and suspension leave a bit to be desired. I don't have the M-sport package (although I did add MPPSK!). I want to sharpen up the steering and stiffen the chassis a bit without setting it up for track. I just don't know where to start. I drive pretty hard on the street, but it sees Chicago winters (and Chicago streets).

Any recommendations?
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      08-13-2020, 09:24 PM   #2
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Congratulations and welcome! My vehicle is 2017 440i Gran Coupe - minus xDrive. "Absolutely love" echoes nicely.

Before making any suggestions, what's your budget for the suspension upgrade?

Does your car have M Adaptive suspension? If yes - the choice of coilovers and shocks will be limited if you want to retain OEM Comfort / Sport functionality to adjust suspension stiffness.

I suggest to review all threads about the classic choices:

- Lowering springs / keep stock shocks (not recommended)
- Lowering springs / replace with shocks which were designed for lowering springs (can work)
- Coilovers

My personal choice would be KW Street Comfort coilovers if your car doesn't have M Adaptive suspension. I had excellent experience with these coilovers. Price: about $1600 + installation + 4 wheel alignment.

https://www.kwsuspensions.com
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      08-14-2020, 01:17 AM   #3
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Tires, depending on what you got on. If you get something with a better tread pattern and stiffer sidewall it can change the cars steering response
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      08-14-2020, 05:48 AM   #4
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Another pair of wheels with summer tread might be cost effective to start. If not you will trash your current tires anyway on a track. If you change your suspension it will make it tough daily driving considering where you live.
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      08-15-2020, 04:18 PM   #5
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Quote:
Originally Posted by cfm56d7b View Post

My personal choice would be KW Street Comfort coilovers if your car doesn't have M Adaptive suspension. I had excellent experience with these coilovers. Price: about $1600 + installation + 4 wheel alignment.

https://www.kwsuspensions.com

I also have KW Street Comfort. Bought my car with the M-Sport suspension but wanted to lower it a bit without sacrificing comfort too much.
Didn't want to go the springs only way and also required the height to be fully adjustable.
The out of the box recommended rebound setting of 9 clicks open from stiff was too soft for me, softer than M-sport. I have adjusted to 7 in front and 5 in the rear. That feels much better, maybe a bit harder/stiffer dan M-sport, not sure. Car feels like it has a little less tendency to understeer so happy about that too!

I do have to say that I think the springs have a slightly lower spring rate than the M-sport springs and sometimes when I go through a high speed corner with some bumps or dips it hits the bump stops quite hard...

Maybe I have to go a couple of clicks down more however don't want to take the rear shocks off again to adjust the rebound...
Should have gotten adjuster extensions

However happy with the comfort level and lowering, that was the goal
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      08-15-2020, 04:35 PM   #6
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Quote:
Originally Posted by Uni-Rapide View Post
I also have KW Street Comfort. Bought my car with the M-Sport suspension but wanted to lower it a bit without sacrificing comfort too much.
Didn't want to go the springs only way and also required the height to be fully adjustable.
The out of the box recommended rebound setting of 9 clicks open from stiff was too soft for me, softer than M-sport. I have adjusted to 7 in front and 5 in the rear. That feels much better, maybe a bit harder/stiffer dan M-sport, not sure. Car feels like it has a little less tendency to understeer so happy about that too!

I do have to say that I think the springs have a slightly lower spring rate than the M-sport springs and sometimes when I go through a high speed corner with some bumps or dips it hits the bump stops quite hard...

Maybe I have to go a couple of clicks down more however don't want to take the rear shocks off again to adjust the rebound...
Should have gotten adjuster extensions

However happy with the comfort level and lowering, that was the goal
My KW Street Comfort coilovers were set at 9 clicks (default). Perfect setting for me at least.

The only disadvantage of KW Street Comfort coilovers is the placement of control knob on the top of the shock. It should have been on the bottom to ease the process of tuning the shock behavior.
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      08-15-2020, 04:49 PM   #7
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Quote:
Originally Posted by cfm56d7b View Post
The only disadvantage of KW Street Comfort coilovers is the placement of control knob on the top of the shock. It should have been on the bottom to ease the process of tuning the shock behavior.
Agreed, in the front it's ok but the rears require the top of the shock to be unbolted to access the adjuster...
So I might end up drilling a hole in the chassis and install the rebound adjuster extensions: https://www.kwsuspensions.net/produc...ers=59,f,51_13
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      08-15-2020, 04:52 PM   #8
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Quote:
Originally Posted by 328iX View Post
Tires, depending on what you got on. If you get something with a better tread pattern and stiffer sidewall it can change the cars steering response
Correct, this combined with wider front tires helps a lot.
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      08-15-2020, 05:43 PM   #9
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Try some monoball thrust arms from VAC or Turner and then better tires.
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      08-17-2020, 04:23 PM   #10
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Quote:
Originally Posted by therealm3 View Post
Try some monoball thrust arms from VAC or Turner and then better tires.
+1 on the bushings. Control and thrust arm especially for steering. the gel filled rubber ones you have in there now are no fun.

if you would like the chassis to absorb less power, you should look at changing the rear subframe and differential bushings as well...it will make the car come alive!!!
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