[stewbets]

Looking for some insight and experience on this one. My first BMW was an E60 545i with sport suspension and active drive and I loved it. I still do, even though I don’t drive it all that often. It’s a great car, but it helped me realize there were 3 features I wanted in a sports car: a manual transmission, a tunable engine, and all-wheel drive. This led me to what I thought was my perfect BMW, the E90 335xi. I bought one of the roughest examples of one, but was able to sort it out over the next year and tune it to make a little over 500awhp. It certainly has the 3 features I was looking for, but it is severely lacking in one that I didn’t even think to include: suspension. It rides like total junk compared to my E60. Bumps are so loud and harsh it makes me think I must have popped a tire or bent a rim just about every time I drive it. It wasn’t until I drove the E60 to work yesterday since I’m fixing a power steering leak in the E90 that I realized how stark the contrast is. So, I finally got around to investigating what kind of suspension my E90 has. I found that it has Bilstein B8 struts with H&R 29187 sport springs. Does this make sense? Is this the reason why my ride quality is crap over any sort of bumps and potholes? Is there a better combination? I can’t figure out how both cars have the same ride height, yet one can handle rough roads and the other can’t. Another question I have is that if the suspensions were equal, would the E60 still feel better than the E90? Does anyone have experience with the two?

[neilvan]

I have an e90 (sport suspension) and an e61 (awd) so kind of the inverse of yours.

The E90 drive and rides way better, I half attribute it to the e90 being smaller/more agile and the e61 being awd(front suspension is different and travel is way shorter due to the front axles being right below the shock). Being lowered and stiffer that is going to only make it more apparent(I also have H&r springs on my E61)

[stewbets]

Originally Posted by neilvan

I have an e90 (sport suspension) and an e61 (awd) so kind of the inverse of yours.

The E90 drive and rides way better, I half attribute it to the e90 being smaller/more agile and the e61 being awd(front suspension is different and travel is way shorter due to the front axles being right below the shock). Being lowered and stiffer that is going to only make it more apparent(I also have H&r springs on my E61)

Now that is interesting. The more I read, I'm seeing that Bilsteins are stiffer than Konis, and H&R's are stiffer than Eibachs. This coupled with the xi is starting to explain the excessively rough ride.

[ppointer]

I have some experience here. Currently own an e60 528, e90 N55 AT, e92 N55 MT and e92 N54 DCT (335is). I just gave our e91 N52 AT to youngest because she needed a car and could not afford one.

The e60 has the sport suspension with 18" wheels from the factory, which should match closely with your car, except we don't have active drive. You might have 19" wheels. This car has stock springs with Bilstein B4's and Michelin Pilot A/S 4's, as well as a recent alignment. Best ride of the bunch (and better than new) and more than reasonable handling. 32 psi front and 38 psi rear for tire pressures.

The e91 has sport suspension with staggered 18" style 193 wheels that I added in place of stock staggered 17". It has brand new B4's, A/S 4's and alignment on original springs. 33 front and 36 rear. Very good ride though just a bit stiffer than the e60. No complaints with rough roads.

The e90 is m-sport and has 75k miles on its original suspension. Has recent A/S 3+'s and alignment. 35 front and 42 rear. I was going to do a suspension refresh, but my dad suddenly needed a car and drives about 300 miles per month. While this car rides well, the rear is not very settled any longer. Medium bumps will pitch it to the side, which I know can be solved with new shocks. I was planning on doing B6's because I had a positive experience with those on my M roadster, but dad doesn't even drive the speed limit at this point.

Both e92's have original suspensions AND original tires, both sets run flats. The MT car is m-sport, and obviously so is the 335is. Both have the worst ride of the bunch, though still controlled over bumps. I plan on new tires for the MT e92 in early fall, at which time it will get A/S 4's. While the ride will be good, I know from experience the shocks will not perform quite as well as the Bilsteins. Will be a few years before either of these e92's get a suspension refresh.

Lastly, all of these e9x's have strut tower braces from ECS Tuning. I never got around to a brace on the e60, but perhaps will later in the year.

To answer your second to last question, your e60 should still have a slightly more compliant ride than your e90 if you were to return the e90 to something approaching stock. If I were trying to create a track car, I would be looking at B8 or B12, or perhaps something from Ohlins, with some kind of a stiff sport spring. My track car would not be something I would want to drive to work any day of the week at my age (60+). But don't lose sight of the tires, as they are also a major factor in how your car carries over bumps. I know from experience that the Pilot Sports ride noticeably stiffer than A/S 3's or 4's, and anything run flat is way worse. (can you tell yet that I hate run flats?)

[ppointer]

Originally Posted by stewbets

Now that is interesting. The more I read, I'm seeing that Bilsteins are stiffer than Konis, and H&R's are stiffer than Eibachs. This coupled with the xi is starting to explain the excessively rough ride.

So, I don't agree with that blanket statement. Each manufacturer makes different model shocks/struts that can correspond to the type of application you're looking for. Since I am more experienced with Bilstein, I can tell you the B4/B6 are closest to the Sachs our cars came with. They are definitely not stiffer, but they are more controlled over bumps. You could get similar results from Koni, too, if you buy their OE-type replacements.

My advice is to consider a balanced approach of springs, shocks/struts and tires. But first, what are you trying to accomplish? For example, if you want to lower your car but have a compliant ride, you're still going to need a sport spring that will be shorter, but stiffer for the available travel you have left. H&R and Eibach will have different models depending on your goals. Match a shock/strut package to that, and add tires to taste (think summer max grip or all-season with more compliance). If you want track capability, perhaps even shorter springs, plus a tunable shock you can easily adjust at the track for rebound and damping.

My approach is stock m-sport springs with OE-type shocks and no run flats. That gives me a compliant ride that is very controlled over bumps, that is better than when the car was new. Perhaps I lose 5% absolute corner traction with A/S's versus Pilot Sports? Since I don't track my cars, I'm not giving anything away that I would miss on the street, while the A/S's are super quiet.

[stewbets]

Originally Posted by ppointer

So, I don't agree with that blanket statement. Each manufacturer makes different model shocks/struts that can correspond to the type of application you're looking for. Since I am more experienced with Bilstein, I can tell you the B4/B6 are closest to the Sachs our cars came with. They are definitely not stiffer, but they are more controlled over bumps. You could get similar results from Koni, too, if you buy their OE-type replacements.

My advice is to consider a balanced approach of springs, shocks/struts and tires. But first, what are you trying to accomplish? For example, if you want to lower your car but have a compliant ride, you're still going to need a sport spring that will be shorter, but stiffer for the available travel you have left. H&R and Eibach will have different models depending on your goals. Match a shock/strut package to that, and add tires to taste (think summer max grip or all-season with more compliance). If you want track capability, perhaps even shorter springs, plus a tunable shock you can easily adjust at the track for rebound and damping.

My approach is stock m-sport springs with OE-type shocks and no run flats. That gives me a compliant ride that is very controlled over bumps, that is better than when the car was new. Perhaps I lose 5% absolute corner traction with A/S's versus Pilot Sports? Since I don't track my cars, I'm not giving anything away that I would miss on the street, while the A/S's are super quiet.

I really appreciate all your input. I'm very ignorant when it comes to suspensions. I found this thread that is pointing toward Bilstein B8's and Eibach Pro's being a great combo:

https://www.e90post.com/forums/showt...light=bilstein

That thread has tons of posts about how harsh the H&R sport springs are, and the consensus is that Eibach Pro's are softer. And it seems most also agree that Konis are softer than their equivalent Bilsteins. This is just what I've picked up. Personally, I don't have a clue.

I like the lowered look that my car has. I'd like to retain it, if possible. But I'd really like to not crash over bumps and road imperfections. I'm not looking to ever track the car, and I'm running Westlake A/S 245/40 R18 tires. If I have to gain a little ride height to improve comfort a little, I'm down with that. I'd prefer to leave the B8's and only consider different springs. Do you think Eibach Pro's would make a difference? Or do you have another recommendation?

[bmw_solid]

Originally Posted by stewbets

I really appreciate all your input. I'm very ignorant when it comes to suspensions. I found this thread that is pointing toward Bilstein B8's and Eibach Pro's being a great combo:

https://www.e90post.com/forums/showt...light=bilstein

That thread has tons of posts about how harsh the H&R sport springs are, and the consensus is that Eibach Pro's are softer. And it seems most also agree that Konis are softer than their equivalent Bilsteins. This is just what I've picked up. Personally, I don't have a clue.

I like the lowered look that my car has. I'd like to retain it, if possible. But I'd really like to not crash over bumps and road imperfections. I'm not looking to ever track the car, and I'm running Westlake A/S 245/40 R18 tires. If I have to gain a little ride height to improve comfort a little, I'm down with that. I'd prefer to leave the B8's and only consider different springs. Do you think Eibach Pro's would make a difference? Or do you have another recommendation?

May be a small thing but check your tyre pressures - inflate them when cold ideally at 20 degrees C - I'm running my E92 SE on 19" wheels 3 psi lower than stock as stock is too firm, crashy and noisy over bumps and excessive road noise (non run flats). As soon as I lowered the pressures to 33 and 36, 80% of those symptoms disappeared (although I have 100% new OEM suspension parts replaced at the front). BMWs and wrong pressures drive like absolute rubbish!! I spent ££££ on new SACHS shocks and lemforder mounts and Febi arms but I think the tyre pressure change was the biggest improvement and that for free!

Now my only concern is keeping the pressures from varying with temperature! When I set them to 33/36 (cold) and drive off, they inflate to 36/39 and all is good. When the temperature goes up or down by 5 degrees or more, then the cold pressures increase/decrease by about 1 bar (remember 0.15 bar per 1 degrees) and the car becomes crashy and road noise is through the roof!!

Besides that, ensure your drop link nuts are tight and the x3 strut mount nuts and the shock nut. Also check for play in your wheel for bad arms - 12-6 o clock shake and 3-9 o clock shake.

Bad tyres also not very good - Michellin PSS4 has best reviews here then followed by Goodyear Eagles and Falken FK510 (non run flat). I wouldn't recommend Kumho or Nexen but would give Hankook S1 Evo 3 (not Evo 2) a try...Falken FK510 seems to be the best all-round tyre and value.

Hope this helps.

[ppointer]

Originally Posted by stewbets

I really appreciate all your input. I'm very ignorant when it comes to suspensions. I found this thread that is pointing toward Bilstein B8's and Eibach Pro's being a great combo:

https://www.e90post.com/forums/showt...light=bilstein

That thread has tons of posts about how harsh the H&R sport springs are, and the consensus is that Eibach Pro's are softer. And it seems most also agree that Konis are softer than their equivalent Bilsteins. This is just what I've picked up. Personally, I don't have a clue.

I like the lowered look that my car has. I'd like to retain it, if possible. But I'd really like to not crash over bumps and road imperfections. I'm not looking to ever track the car, and I'm running Westlake A/S 245/40 R18 tires. If I have to gain a little ride height to improve comfort a little, I'm down with that. I'd prefer to leave the B8's and only consider different springs. Do you think Eibach Pro's would make a difference? Or do you have another recommendation?

I would recommend calling Tire Rack. They have experts on hand that can listen to what you want to accomplish and then make some recommendations. I do not recommend shopping by brand. Instead, shop by what you are trying to accomplish, because they all offer good products with different applications. In other words, don't just buy Eibach because someone said they are softer. Or that Koni's are softer than Bilsteins. I promise you there are firm Koni's and soft Bilsteins. Don't want to make an expensive mistake.

I did a brief search based on one of my cars, and you can see a wide variety of options:

https://www.tirerack.com/suspension/...+Sport+Package

[andykrow]

It's really easy to pull struts on this car. If I were you I might start by checking to be sure your B8's aren't blown.

i haven't tried much suspension-wise on my 335xi, but from research it seems that lowering that suspension and keeping the "pothole crash" from happening is a tall order. The issue being xi suspension is already reduced travel compared to rwd.

Mine is an m-sport although those have stock height springs in the XI. Before I replaced the struts I had crazy tooth-jarring pothole crash on everything. Seeing bridge expansion plates ahead would give me serious anxiety lol

So, given that I did not want to lose the tiny amount of uptravel I currently have I decided to stick with stock springs in my car. I went with the Bilstein B4 struts which are 10% stiffer than stock. I'm considering trying out Koni next season as I would like a touch more stiffness but the B4 is pretty decent. I just don't want the shock so stiff it induces the pothole crash on it's own, and there are some reports that B6/B8 can do that on this platform. That's going to vary by the specific spring you run.

The struts I pulled were completely blown out too... Like, very little resistance. They were doing nothing. With the B4's the crash is completely gone. Still a bit rough over the roughest of roads but it's a sports sedan so that is to be expected.

[stewbets]

Originally Posted by andykrow

It's really easy to pull struts on this car. If I were you I might start by checking to be sure your B8's aren't blown.

i haven't tried much suspension-wise on my 335xi, but from research it seems that lowering that suspension and keeping the "pothole crash" from happening is a tall order. The issue being xi suspension is already reduced travel compared to rwd.

Mine is an m-sport although those have stock height springs in the XI. Before I replaced the struts I had crazy tooth-jarring pothole crash on everything. Seeing bridge expansion plates ahead would give me serious anxiety lol

So, given that I did not want to lose the tiny amount of uptravel I currently have I decided to stick with stock springs in my car. I went with the Bilstein B4 struts which are 10% stiffer than stock. I'm considering trying out Koni next season as I would like a touch more stiffness but the B4 is pretty decent. I just don't want the shock so stiff it induces the pothole crash on it's own, and there are some reports that B6/B8 can do that on this platform. That's going to vary by the specific spring you run.

The struts I pulled were completely blown out too... Like, very little resistance. They were doing nothing. With the B4's the crash is completely gone. Still a bit rough over the roughest of roads but it's a sports sedan so that is to be expected.

Wouldn't blown struts create a bouncy ride after hitting bumps? Did you experience this before replacing yours? I get what you're saying about the reduced strut travel on the xi. It's just not ideal, especially when combined with lowering springs.

[stewbets]

Originally Posted by bmw_solid

May be a small thing but check your tyre pressures - inflate them when cold ideally at 20 degrees C - I'm running my E92 SE on 19" wheels 3 psi lower than stock as stock is too firm, crashy and noisy over bumps and excessive road noise (non run flats). As soon as I lowered the pressures to 33 and 36, 80% of those symptoms disappeared (although I have 100% new OEM suspension parts replaced at the front). BMWs and wrong pressures drive like absolute rubbish!! I spent ££££ on new SACHS shocks and lemforder mounts and Febi arms but I think the tyre pressure change was the biggest improvement and that for free!

Now my only concern is keeping the pressures from varying with temperature! When I set them to 33/36 (cold) and drive off, they inflate to 36/39 and all is good. When the temperature goes up or down by 5 degrees or more, then the cold pressures increase/decrease by about 1 bar (remember 0.15 bar per 1 degrees) and the car becomes crashy and road noise is through the roof!!

Besides that, ensure your drop link nuts are tight and the x3 strut mount nuts and the shock nut. Also check for play in your wheel for bad arms - 12-6 o clock shake and 3-9 o clock shake.

Bad tyres also not very good - Michellin PSS4 has best reviews here then followed by Goodyear Eagles and Falken FK510 (non run flat). I wouldn't recommend Kumho or Nexen but would give Hankook S1 Evo 3 (not Evo 2) a try...Falken FK510 seems to be the best all-round tyre and value.

Hope this helps.

I can play around with tire pressure and see what happens. Thanks for the tip!

[ppointer]

Originally Posted by stewbets

Wouldn't blown struts create a bouncy ride after hitting bumps? Did you experience this before replacing yours? I get what you're saying about the reduced strut travel on the xi. It's just not ideal, especially when combined with lowering springs.

I had struts/shocks nearly lock up on my e46 touring some years ago. After 180k miles I wasn't surprised they failed, but surprised they would barely move. Obviously I went way too long to do the suspension refresh on that car.

[andykrow]

Originally Posted by stewbets

Wouldn't blown struts create a bouncy ride after hitting bumps? Did you experience this before replacing yours?

It was not really as bad as you would expect, strangely enough. Definitely did not feel like completely blown out pogo sticking. Just less control than I would like and terrible pothole crash. Could definitely tell they were on the way out. I think this design relies on compression damping to stop the bottom out and that was certainly toast. After I got the coils off I could compress the strut with my pinky it was so weak.

I replaced the bump stops too so I'm sure that helps with mitigating the crash.

Regarding bounciness it would probably depend on how the shock specifically failed as to what effect you would get. Presumably if it's just low on oil (not completely empty) the initial compression will be pushing air though the compression circuit so no damping at all, and by the time some oil gets to the circuit it's moving too fast to stop the bottom out. Conversely, rebound on deep hits will have oil available immediately, even if it's low, and rebound is what controls the bounce.

[whyzee125]

I've had a number of suspension setups and the best riding setup was Tein S tech springs with Koni shocks and the e30 perches and pads up front for a little additional ride height. Sat about like H&R sport in the rear and a tad higher up front. Ride was as good or better than stock.