[br4to92]

Hello, for over more than one and a half year I'm running my 2014 BMW F30 320d with a pair of static BMW M Sport shocks with Eibach Sportline coilovers (the red ones), which are a bit shorter than the standard Eibach Pro Kit coilovers. Not long ago a mechanic told me that both the front shocks had leaked, and I'm curious if that could be from the short springs, or it could be from something else. If the springs are too short I'm thinking to replace them with the original M Sport springs that came paired with the M Sport shocks. Does any of you have any ideas? Thanks.

[pauli18c]

That could definitely have contributed as the stock shocks are not meant for lowering springs but there's many factors, age being the one that sticks out to me. Being as it's a 2014, that would have me thinking the shocks are old and just time to be replaced anyways. How many miles are on the car?

Why not just get shocks that are made for the springs if you like how the car rides and sits? Like the Bilstein B8, which is made for lowering springs like you have.

[br4to92]

The M Performance shocks were not stock on the car when it was made. I put them just about one and half years ago (when I also added the Eibach springs). I bought them used but in good condition from a guy that replaced them with Bilstein shocks (if I remember correctly they came from a BMW F22 M240i with less than 50k kilometers). I remembered the seller said that one of the front shocks was replaced with a brand new one not long before he sold them to me. Also the mechanic that installed them in my car didn't say anything that they were worn out or in bad condition, so I think they were fine when I got them.
Anyway, I chose the M Sport shocks over the Bilstein ones because I got a good deal on them being sold as second hand (less than half the price of the Bilstein). So I guess at this point I either have to replace the leaking shocks with the same model and put the M Sport springs that I already have, which would be the less expensive option, or buy a new set of Bilstein shocks for all the four wheels and use them with my Eibach Sportline springs.

[johnung]

Originally Posted by br4to92

The M Performance shocks were not stock on the car when it was made. I put them just about one and half years ago (when I also added the Eibach springs). I bought them used but in good condition from a guy that replaced them with Bilstein shocks (if I remember correctly they came from a BMW F22 M240i with less than 50k kilometers). I remembered the seller said that one of the front shocks was replaced with a brand new one not long before he sold them to me. Also the mechanic that installed them in my car didn't say anything that they were worn out or in bad condition, so I think they were fine when I got them.
Anyway, I chose the M Sport shocks over the Bilstein ones because I got a good deal on them being sold as second hand (less than half the price of the Bilstein). So I guess at this point I either have to replace the leaking shocks with the same model and put the M Sport springs that I already have, which would be the less expensive option, or buy a new set of Bilstein shocks for all the four wheels and use them with my Eibach Sportline springs.

I assume that your car is RWD because the lower red Eibach springs are usually too low for XDrive. BMW dampers aren’t designed with enough travel to drop them that much without quickly wearing out. If you like the red Eibach’s so much, consider getting Koni Yellow Sport adjustable dampers. They are designed to handle drop like the Bilstein B8’s. But the B8’s are set up very stiff from the factory, and are not adjustable for comfort like the Konis.

[johnung]

Originally Posted by br4to92

The M Performance shocks were not stock on the car when it was made. I put them just about one and half years ago (when I also added the Eibach springs). I bought them used but in good condition from a guy that replaced them with Bilstein shocks (if I remember correctly they came from a BMW F22 M240i with less than 50k kilometers). I remembered the seller said that one of the front shocks was replaced with a brand new one not long before he sold them to me. Also the mechanic that installed them in my car didn't say anything that they were worn out or in bad condition, so I think they were fine when I got them.
Anyway, I chose the M Sport shocks over the Bilstein ones because I got a good deal on them being sold as second hand (less than half the price of the Bilstein). So I guess at this point I either have to replace the leaking shocks with the same model and put the M Sport springs that I already have, which would be the less expensive option, or buy a new set of Bilstein shocks for all the four wheels and use them with my Eibach Sportline springs.

The Koni Sport Yellow part numbers that you would need are probably one of these two part numbers in photos. I would send your VIN to Koni and ask the differences between the two. Your car originally came without the M Sport Suspension so that’s probably the part number that they might recommend. But since you have the Eibach red springs, the Konis for the M Sport suspension might be better for your setup

[br4to92]

Originally Posted by johnung

I assume that your car is RWD because the lower red Eibach springs are usually too low for XDrive. BMW dampers aren’t designed with enough travel to drop them that much without quickly wearing out. If you like the red Eibach’s so much, consider getting Koni Yellow Sport adjustable dampers. They are designed to handle drop like the Bilstein B8’s. But the B8’s are set up very stiff from the factory, and are not adjustable for comfort like the Konis.

Yes, my car is RWD, not XDrive. My thought was to remain on the M Sport shocks and use the springs that came with them instead of keeping the red Eichachs and buy a new set of shocks for all the 4 wheels. This option might be the least expensive since I only have to buy a set of M Sport shocks for the front wheels.
My question then is if keeping the M Sport shocks + springs would keep the car's stability similar to using the Eibach springs with a compatible set of shocks like the ones from Blistein or Koni.

[Z K]

Originally Posted by br4to92

Yes, my car is RWD, not XDrive. My thought was to remain on the M Sport shocks and use the springs that came with them instead of keeping the red Eichachs and buy a new set of shocks for all the 4 wheels. This option might be the least expensive since I only have to buy a set of M Sport shocks for the front wheels.
My question then is if keeping the M Sport shocks + springs would keep the car's stability similar to using the Eibach springs with a compatible set of shocks like the ones from Blistein or Koni.

I don't know about "stability" but it would be no different than the M sport shocks and springs that come standard on the F30 with M Sport. The Eibach is lower and possibly stiffer ride than the standard M Sport.

[br4to92]

Originally Posted by Z K

I don't know about "stability" but it would be no different than the M sport shocks and springs that come standard on the F30 with M Sport. The Eibach is lower and possibly stiffer ride than the standard M Sport.

By stability I was meaning that the car should incline less when taking turns.

[johnung]

Originally Posted by br4to92

By stability I was meaning that the car should incline less when taking turns.

Then what you are referring to as stability is called body roll. You should have more body roll with the higher M Sport springs & dampers than with lower red Eibach springs and Koni Yellow Sport dampers. I definitely would not use Bilstein B8’s. They are fixed at a stiff setting at the factory with no way to adjust if you don’t like it. While the Koni Yellows have an entire range of adjustments that you can make.

[br4to92]

Originally Posted by johnung

Then what you are referring to as stability is called body roll. You should have more body roll with the higher M Sport springs & dampers than with lower red Eibach springs and Koni Yellow Sport dampers. I definitely would not use Bilstein B8’s. They are fixed at a stiff setting at the factory with no way to adjust if you don’t like it. While the Koni Yellows have an entire range of adjustments that you can make.

Since I'll get less body roll if I stick with the shorter red springs I guess I'll have to choose between the Koni or Bilstein B8's. From what you are saying I assume that Bilstein shocks are stiffer than the M Sport ones. Interesting, so far I never felt that the M Sport shocks are too stiff, I expected them to be harsher since they are sport suspension but they seemed similar to the stock shocks I had by default on the car. Maybe it's because the Eibach springs, the mechanic told me back then when he installed the suspension that he was surprised that the red springs are so comfortable for a sport suspension.

[djacinto]

Originally Posted by br4to92

Since I'll get less body roll if I stick with the shorter red springs I guess I'll have to choose between the Koni or Bilstein B8's. From what you are saying I assume that Bilstein shocks are stiffer than the M Sport ones. Interesting, so far I never felt that the M Sport shocks are too stiff, I expected them to be harsher since they are sport suspension but they seemed similar to the stock shocks I had by default on the car. Maybe it's because the Eibach springs, the mechanic told me back then when he installed the suspension that he was surprised that the red springs are so comfortable for a sport suspension.

If you are worried about body roll, you could do stiffer sway bars and bushings, or a strut brace. The latter has less impact, but is less involved and much much cheaper.

I have found with the install of my koni SA and the strut brace, car corners very very flat now.

[br4to92]

Originally Posted by djacinto

If you are worried about body roll, you could do stiffer sway bars and bushings, or a strut brace. The latter has less impact, but is less involved and much much cheaper.

I have found with the install of my koni SA and the strut brace, car corners very very flat now.

I already have Eibach's red sway bars installed at the same time I did the suspension and more recently I also added a strut brace. I compared my car to a stock Mercedes-Benz C-Class W205 with only a set of Eibach Pro Kit springs (which are not as short as my Eibachs Sportline) and interesting enough I felt that my car rolls over more than that one at relatively higher speeds, despide all the upgrades I have on mine.

[johnung]

Originally Posted by br4to92

Since I'll get less body roll if I stick with the shorter red springs I guess I'll have to choose between the Koni or Bilstein B8's. From what you are saying I assume that Bilstein shocks are stiffer than the M Sport ones. Interesting, so far I never felt that the M Sport shocks are too stiff, I expected them to be harsher since they are sport suspension but they seemed similar to the stock shocks I had by default on the car. Maybe it's because the Eibach springs, the mechanic told me back then when he installed the suspension that he was surprised that the red springs are so comfortable for a sport suspension.

Yes, BMW M Sport suspension components are an incremental improvement, not anything abrupt. I’d call them pretty mild.

Eibach does an excellent job picking their spring kits for the axle weights of various BMW models. And Eibach’s are typically a slightly higher spring rate than stock, maybe 10%. So the result is lowering with more control but not something that is an abrupt harsh change. Spring kits from H&R, Dinan, etc tend to be 30%, 50% or more higher spring rates so they can be adrift harsh changes in ride.

Dampers can be similar. M Sport are an incremental improvement over stock dampers but not monumental. Koni Special Active are a big improvement in sportiness and comfort at the same time because of their unique design. Koni Yellow Sport are adjustable for comfort and lean towards sportiness. Bilstein B4 are their replacement shock. I’m not fond of the stock shocks anyway. Bilstein B6/B8 are their sport shocks and are more abruptly stiff/harsh. Fixed with no adjustment.

Suspensions are actually very complex with many interactive components including tires, wheels, brakes (unsprung & rotational weight effects). One can easily make a poor component choice. Luckily there’s a finite number of reasonably priced mod choices.

I found the stock chassis and suspension with the runflat tires to be too stiff/uncomfortable with way too much body roll in curves and very vague steering. In my mod choices on my daily driver, I’ve tried to increase comfort, while improving cornering and steering.

Hope this helps!

[johnung]

Originally Posted by br4to92

I already have Eibach's red sway bars installed at the same time I did the suspension and more recently I also added a strut brace. I compared my car to a stock Mercedes-Benz C-Class W205 with only a set of Eibach Pro Kit springs (which are not as short as my Eibachs Sportline) and interesting enough I felt that my car rolls over more than that one at relatively higher speeds, despide all the upgrades I have on mine.

It’s tough to compare two different car makes that way because their suspensions are engineered differently. If you already have Eibach sways and a top strut brace on the car you shouldn’t be feeling like body roll is excessive. The blown BMW dampers are an obvious problem that Konis will fix.

If you are running stock size tires 225/45-18 that is definitely contributing to body roll. I ditched my stock runflat 225/45-18 on 400M 18x8 ET34 for non-runflat 245/40-18 Michelin Pilot Sport 4S on the same wheels. Soon I’ll be going to new wheels with 255/40-18 MPS4S. (Continental DWS06+ are an all season performance tire option) Wider tires work with the suspension additions. They are a necessary upgrade if you want to maximize your suspension mods.

[br4to92]

Originally Posted by johnung

It’s tough to compare two different car makes that way because their suspensions are engineered differently. If you already have Eibach sways and a top strut brace on the car you shouldn’t be feeling like body roll is excessive. The blown BMW dampers are an obvious problem that Konis will fix.

If you are running stock size tires 225/45-18 that is definitely contributing to body roll. I ditched my stock runflat 225/45-18 on 400M 18x8 ET34 for non-runflat 245/40-18 Michelin Pilot Sport 4S on the same wheels. Soon I’ll be going to new wheels with 255/40-18 MPS4S. (Continental DWS06+ are an all season performance tire option) Wider tires work with the suspension additions. They are a necessary upgrade if you want to maximize your suspension mods.

Thanks for all the information so far! Regarding wheels and tires, I have 255 on the back, 225 on front, both 18, both with normal tires (not runflat). I guess you have same size on both since yours is xDrive. My car came very stock by default, with 205 on 16 inch and replacing them was my first mod, although my EfficiendDynamics model does not officially recognise other dimensions besides the small 205 on 16 ones. Anyway, since you mentioned all season tires, I had in mind moving to all seasons so I won't need to switch between summer/winter tires. Are those Continental DWS06+ good on snow or ice? It's not really snowing a lot in my area but it would be nice to be covered when the road is icy. I read about Michelin's CrossClimate's and I saw some good reviews on them.

[johnung]

Originally Posted by br4to92

Thanks for all the information so far! Regarding wheels and tires, I have 255 on the back, 225 on front, both 18, both with normal tires (not runflat). I guess you have same size on both since yours is xDrive. My car came very stock by default, with 205 on 16 inch and replacing them was my first mod, although my EfficiendDynamics model does not officially recognise other dimensions besides the small 205 on 16 ones. Anyway, since you mentioned all season tires, I had in mind moving to all seasons so I won't need to switch between summer/winter tires. Are those Continental DWS06+ good on snow or ice? It's not really snowing a lot in my area but it would be nice to be covered when the road is icy. I read about Michelin's CrossClimate's and I saw some good reviews on them.

I have heard people whom I trust, say good things about both of those tires. So you probably can’t go wrong either way. I suggest digging deeper on the TireRack website, comparing the two. That will tell you how they rank on the features most important to you.

Also this YouTube channel has really excellent/professional tire reviews. I’m sure that he has done videos on both tires.

https://youtube.com/@tyrereviews

[br4to92]

Originally Posted by johnung

I have heard people whom I trust, say good things about both of those tires. So you probably can’t go wrong either way. I suggest digging deeper on the TireRack website, comparing the two. That will tell you how they rank on the features most important to you.

Also this YouTube channel has really excellent/professional tire reviews. I’m sure that he has done videos on both tires.

https://youtube.com/@tyrereviews

Thanks, I had a look on that channel and it seems that the Micheling CrossClimate 2 are indeed the best choice of all season tires.

[br4to92]

I have one more question, as it turns out it is a bit hard to find shorter shocks for my Eibach sportline springs, I'm wondering if replacing the springs with the Eibach pro kit ones which are longer would work with the factory M Sport shocks. I could do that instead.