01-13-2023, 01:34 PM | #1 |
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Suspension / Shock Absorber advice - rough ride
2017 F30 LCI MSPORT
Hi I’m looking for some advice on how I can make my drive feel more comfortable. I love my f30 but ever since I got it one thing just hasn’t sit right with me and that’s how rough the ride is. It just harsh and it’s sucks tbh. I’m not driving the car on track or anything I use it for everyday day to day use and I feel every bump in the road. It’s such a rough drive. I would have expected it to have been smoother and not as harsh. (There’s not issues with the car) That’s lead me to trying to figure out what my options are to make it smoother without breaking the bank like crazy. My current options from research 1. I have 19inch run flats - a lot of people have told me to get rid of the runflats but that’s not so easy… I have four decent tyres and don’t want to just get rid and replace right now - however I’m open to the idea 2. Bilsteins - I didn’t know much about these but I’m told I could change the dampers/shock absorbers. I don’t know which ones will actually help me for a smoother ride and I’ve seen some say it’s made the suspension even stiffer. - I don’t want to lower the car for any aesthetic reasons so my research so far has lead me to the b6 (but is that the right one for f30 m sport, as I’ve read b8 should be used as it’s slightly lower and as it’s closer to the m sport set up? Could be wrong) - then question is do I need to new springs as well? Or can I use my existing ones? Would the bilsteins help with making the bumps in the road feel less harsh Also would I need to change the front and back absorbers? Or can I get away with doing the front only? What are your thought and recommendations on what I could do? Last edited by Razinho; 01-13-2023 at 01:46 PM.. Reason: Accuracy |
01-13-2023, 05:01 PM | #2 |
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It's helpful to learn what your budget is first ...
Comfort is a very subjective measure but I sense you are dissatisfied because the suspension doesn't react quickly enough to road imperfections: rapid enough compression to absorb the the bump and rapid enough rebound to maintain suspension geometry and ensure the tire contact with the rod surface. The outcome is very predictable: the vehicle bounces and continue to bounce because the suspension always lags reacting to road imperfections. While there isn't a perfect answer, the options are ... 1. 18" wheels with non run flat tires - Bigger sidewall will help reduce the harshness 2. Aftermarket shocks and springs - I suggest to search posts from johnung and read https://f30.bimmerpost.com/forums/sh....php?t=1675667 sharing positive experience with Koni Special Active shocks and Eibach springs. - Do not recommend Bilstein B6 shocks. B6 shocks are stiffer than OEM. B8 shocks are shorter and require a lowering spring (stiffer still), producing an even stiffer ride. 3. Coilovers - Much more expensive solution but can work if coilovers provide independently adjustable compression and rebound controls: worth exploring KW V3 coilovers if within the budget. - Will lower your vehicle and may not be a good fit based on your requirements |
01-13-2023, 06:23 PM | #3 | |
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Even since my wife and I committed to our BMW being our daily driver/family trip car I have been on a mission to make it as smooth and comfortable as possible while still handling amazingly. Below is the mod list to accomplish this: Koni Special Active Struts/Shocks Eibach Springs If >50k miles, replace stock rubber spring perches, etc. 18” wheels, square setup 1st) Stock BMW 400M 18x8.0 with 245/40-18 Later) Apex 18x8.5 255/40-18 Michelin Pilot Sport 4S If I was going all seasons: Conti DWS06+ The Apex/MPS4S setup cuts 11+ lbs/corner of rotating mass for better acceleration and handling. Also for handling & steering: H&R Front 28mm sway bar KC Design Rear 17mm sway bar Weichers Front Strut Brace VAC Monoball Front Upper & Lower Control Arms KC Design Adjustable Sway Bar Links I started with the Koni Special Actives, Eibach Springs and square non-runflat MPS4S 245/40-18, and the ride improved tremendously. Hope this helps! |
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01-13-2023, 07:33 PM | #4 | |
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Thank you for sharing! And yes that is the reason just always feel like a heavy thud for the smallest of bumps in the road. It’s quiet annoying and can only ignore for so long. |
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01-13-2023, 07:34 PM | #5 | |
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I’ll check out the Koni and eibach set up! |
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01-13-2023, 07:42 PM | #6 | |
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01-14-2023, 04:27 AM | #7 | |
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https://larkspeed.com/shopper/i/459B...k-Absorber-Kit Is this the ones you refer to? The naming conventions get a bit confusing. Also I have the msport 320d and I believe it’s not the adaptive suspension but the msport range is lowered naturally a bit. Could I use the existing m sport springs with these konis? And change to springs later? Which Eibach springs did you use? I ask as if it won’t be detrimental I can spread the work cost out. What were the other parts one should consider to change as you hinted to above, Around the shocks (perches etc) ? This way I don’t have to act like I know what I’m talking about to the mechanic and can ask him to directly check if those are worn out too �� My cars now at 53k Last edited by Razinho; 01-14-2023 at 04:31 AM.. Reason: Typo |
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01-14-2023, 07:52 AM | #8 | |
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01-14-2023, 03:35 PM | #9 |
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01-14-2023, 07:02 PM | #10 |
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Your link shows Koni Special Actives but the wrong part number because your VIN shows that your car has the M Sport Suspension. See photos for correct M Sport F & R Koni part numbers.
You said that you don’t want to lower, so just stick with your stock M Sport springs with the Koni SA’s. I attached the part numbers for Eibachs if you ever want to lower but no reason to. I also attached the part numbers for front and rear spring perches. Most mechanics will just re-use the old ones because they will probably appear fine. But they are over six years old and rubber loses its resiliency so refreshing them with new helps comfort. Learned this from a buddy who owns a BMW shop. When you eventually ditch the runflats it will improve comfort too. Hope this helps! |
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01-15-2023, 08:27 AM | #11 | |
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01-15-2023, 08:46 AM | #12 |
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Just to add to all the great info here, I strongly recommend wheels and tires before ordering any suspension components. Since your goal is just comfort and you don’t want to drop it, this may be enough for your needs. If you still feel it’s not smooth enough, you can dive into suspension parts mentioned here. 18x9 or 18x8.5 lightweight flow formed wheels with 255/40 is a great approach. Lots of options at 18x8.5 et35 which which would look best on a stock height car. I have DWS06+ on my car and love them as a year round tire so far (haven’t tried them in the snow yet). A cheaper option would be some oem 18s with factory sizes. Good luck
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01-15-2023, 09:37 AM | #13 | |
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His car has 53k miles so the cheap stock dampers are at end of life so his car would really benefit from the Koni SA’s right now. I upgraded to Koni SA’s while I still had runflats and the new damper noticeably improved the ride. As you mentioned, if he found say a used set of square BMW 400M 18x8 ET34 for around $600, he wouldn’t have to go with the stock 225/45-18 size. 235/45-18 would provide more comfort and handling. 245/40-18 would provide more comfort than runflats along with best handling size. (8.5” width wheels are required to go with 255/40-18) Note: Using BMW stock wheels doesn’t provide the potential savings in rotational mass/unsprung weight. Stock 400M’s weigh 26.0lbs each. The 18x8.5” wheels that I would consider weigh between 17.6lbs-19.6lbs. There’s even about a 2lb savings going from runflat 225/45-18 to larger non-runflat 255/40-18. Those stiff runflat sidewalls weigh a lot! |
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01-15-2023, 05:22 PM | #14 |
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Great advice from all
Definitely taking it all onboard just a case of what can I do now and what I can do later. At the moment have 19 wheels (came as when I bought the car) and 4 healthy RF tyres. I may switch up the wheels when the tyres degrade a bit more. [At the front it has 225/40/19 and at the back 255/35/19] But yeah I think I could do with the dampers/shocks. I think it’s make sense to change the Springs too, maybe… given I’d do the dampers. However I must say it’s been a bit of pain trying to figure out part numbers for the springs as the Koni Active work with OEM springs for the model with m tech as they call it (m suspension) a lot of options im finding lower the car. @johnung kindly shared some springs options above but I wonder how different/lower are they to the ones I have with the car assuming they are stock m suspension set up ones. Last edited by Razinho; 01-15-2023 at 05:28 PM.. |
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01-15-2023, 06:18 PM | #15 | |
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What’s the purpose of thicker sway bar since the car comes with stock sway bar?
Also you don’t install front lower strut brace? Thanks. Quote:
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01-15-2023, 07:40 PM | #16 | |
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If you read that Koni SA’s are only for “stock height” springs, ignore that! That’s what I call German translation speak! Believe me. I’ve spoken to Koni tech support several times on this subject. They consider moderate drops to be in the category of stock height springs. It is very important though during the installation to trim about 1/2” off the top of each bump stop with a serrated knife. This assures that the SA’s won’t prematurely hit the bump stops and get confused thinking that the road is rougher than it is. See attached photos. The Koni Special Actives are a passive damper meaning that they have no electronics and no electrical connection. They use a technology that Koni developed with McLaren. It uses two valves tuned to different frequencies. One senses rough road frequencies and reacts like a comfort shock. The other valve reacts to frequencies from twisties so it becomes a Sports shock. Best of both worlds. It’s not just marketing hype. When you drive the car on different roads that is exactly how the Koni Special Actives feel. It’s important to take measurements of the stock chassis height at all four wheels so that you know your original starting points. It’s not uncommon for left and right measurements to differ so don’t be concerned if they do. Fill up your gas tank. Fuel weighs about 100 lbs. Fill up before you take any measurements in the future for consistency. Park on a flat surface. With a tape measure obtain the exact distance from the center of the BMW wheel cap straight up to the closest spot on the fender lip. This chassis height distance will not change regardless if wheels and tires were to change. Take an “after” measurement after new dampers/springs are installed, and a few weeks later to see if any settlement has occurred (which can happen/is normal) I also included some BMW stock spring vs Eibach spring comparison photos. Hope this helps! |
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01-15-2023, 08:24 PM | #17 | |
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Stock BMW sway bars tend to be undersized so there is too much body roll, especially when the engine is tuned for more power and the driver wants to take turns more aggressively. I’ve attached comparison photos of stock vs upgraded sway bars. Most cars have easy access to sway bars so labor is minimal. But in the BMW F30 the sway bars are buried so many components need to be removed to get to the stock sway bars to swap them out for upgraded sway bars. The front sway is more difficult to access than the rear sway bar. IMO since labor is more costly, people often ignore sway bar upgrading and instead overcompensate with heavy springs and heavy dampers in an effort to reduce body roll. The problem is that causes stiff/harsh ride all of the time, even when the car is going in a straight line. Note: I only use solid steel sway bars because hollow sway bars have been known to suddenly snap. It’s a big safety issue with me. I lost a friend when a front suspension component on his car snapped and sent his car head-on into a concrete barrier at 50mph. There’s no need for a lower strut brace. The stock suspension essentially forms a “U” shape with the vertical strut towers forming the vertical sides which have an initial flex when the car first enters a turn. A front top strut brace connects the tops of the sides forming more of a square. By reducing/eliminating that initial flex, it feels to the driver like the steering is quicker because the car enters turns quicker. Hope this helps! |
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01-16-2023, 08:54 AM | #18 |
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I'm also from the UK and daily a 2016 330d M Sport on 19" runflats.
How many miles on yours? If it's past 60K, chances are the dampers are tired. I would not touch the suspension if you're aiming for a smoother ride, it's not going to happen. How it is now, unless the dampers are fooked, is as smooth as it gets. The best you can do is try non run-flats, and I would suggest it's not THAT bad a problem if you are willing to wait until they've worn out first? Anyone annoyed that much by runflat harshness would ditch them immediately. If that is unacceptable, then you need a different car, sorry. You know how sh1t UK roads are, so don't be in denial that aftermarket parts will be the magic bullet, because they most certainly aren't. They just make things worse. |
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01-16-2023, 09:35 AM | #19 | |
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1) As others have noted, it is the tires first and foremost that have the greatest impact on ride smoothness. Depending on year and configuration, BMW altered both tire and wheel sizes on the F30. One combination has been the use of runflat tires with 19-inch wheels, a configuration BMW would have known to be uncomfortable on city streets for the average buyer. To resolve that problem, it appears BMW softened up the springs considerably. The downside to this choice is that softer springs with mild dampers allow for greater roll, a complaint noted by many F30 enthusiasts whose cars came with runflat tires. Interestingly enough, in the final 2 years of the F30 340/340ix, the car came with go flat tires and stiffer springs. The G20 340? Comes with go flat tires and stiffer springs. If a major car maker can't get runflats to be comfortable, you can try, but I doubt you'll have much luck. 2) You can opt for a spring-damper replacement, with Ohlins Road and Track coilovers being highly rated for both ride comfort and sportiness. Outside of a custom damper, these are considered one of the best suspensions available. But, they are likely one of the most expensive upgrades you will make to an F30. The F30 is roughly a 40-50K car. The Ohlins are made for cars $60k and up. It's not really a surprise they are so good. That being said, complaints of early (less than 2 yrs use) rebuilds are a more common than you'd expect for such an expensive product. Hard to say if this is due to overaggressive use, incorrect installation, or the price one pays for such a product. If comfort is the goal, a cheaper alternative is to use Bilstein B4 shocks, leaving the factory springs. The B4 is equivalent to the currently installed Sachs shocks and competitively priced and often available from many retailers. As suggested by others, replace all rubber bushings and mounts including the top hats front and rear. The Koni Special Actives have also been praised as having OE comfort and additional sportiness and are reasonably priced. Adjustable suspensions are the next tier up and, if you really want to learn more about suspensions and how settings affect the ride, I'd recommend them. But if all you want is a comfortable ride, it's a feature you'll pay for but will never use. 3) Since your car rests on it's springs changing their length changes the degree of roll and pitch. Shorter will reduce the amount of roll and pitch the car can have. If roll and pitch are something you consider a current problem, a shorter spring can help solve that issue. If this is not a problem for you, do not change the springs. Shorter springs can be stiffer. A taller spring has more space to compress so it can have lower spring rate. If a short one compressed at the same rate, the coil will bind and the car will bash into it's bump stops. A shorter spring will want to resist compression more than a taller one to avoid this problem. Keep in mind due to this change in rate of compression (and decompression) a change in the damper is usually required. The forum is a friend here with many reporting results of spring-damper combos they found favourable in terms of handling and acceptable in terms of comfort. 4) Replacing the thrust arm bushings (1 per side) will tighten up the handling but will also increase interior cabin noise. At first, when you go from the hydro bushing to the monoball bushing, it seems the increase is minimal. In my experience though what is happening is when you go from an old worn hydro bushing, to a monoball the increase is minimal because the hydro bushing is already starting to wear and creating more noise. Go from the monoball to a new hydro bushing and you will likely discover the damping effect is noticeable. While the handling is a little less sharp I would not call it sloppy. Of course, this is an opinion. I did not find the softening of the bushing to negatively affect handling to a degree I found unacceptable and I did like the decreased noise. An in-between choice is PowerFlex polyurethane bushings, which I am considering because I know once those hydro bushing hit the track, they'll be dead by weekend #4. Good luck.
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Last edited by casualDIYer; 01-16-2023 at 02:43 PM.. |
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01-16-2023, 05:26 PM | #20 | |
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I get what you’re saying but it’s not necessarily true regarding aftermarket parts, their are offerings out there that will improve the ride but Ofc depends on what you’re willing to spend. I like my car, a lot I don’t need to get rid of it’s a case of trying to find out what my options are for a better drive like what you suggested and Jonhnung shared etc, because as of right now it’s terrible drive and yes UK roads mate are shxte . |
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01-16-2023, 05:47 PM | #21 |
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FYI- When you read comments that a particular coilover is comfortable the key question is “Comfortable compared to what?” Coilovers in general are designed with much higher spring rates and many have mismatched dampers. They are inherently harsher.
If I was going to choose a coilover for comfort I would choose the KW V2 Street Comfort. It would be more comfortable than other coilovers but not as comfortable as the Koni Special Actives with stock springs or Eibach springs. FaRKle! has written some excellent posts on this subject. One of them compares the Koni Red Special Actives to the Koni Yellow Sport shocks. The SA’s have no user settings, their two frequency valves are factory set. However the Yellow Sports are user adjustable for comfort. So guys will often assume that if they are prioritizing comfort they should get the Yellow Sports because they could adjust them to the most comfortable setting and be more comfortable than the SA’s, but that isn’t true. In actuality the two dampers overlap quite a bit but the range of the SA’s dips further into the comfort zone while the Yellow Sports dip further into the sport zone. So I often recommend to get the Yellow Sports if a car will be weekend tracking. It’s nice to be able to adjust the dampers from a preferred daily driver setting to a preferred tracking setting. But if a car is primarily a daily driver (like my own), the Special Actives can best handle rough potholes while still adjusting themselves to handle a sporty curve. Note: Koni Yellows and Bilstein B8 are often considered by guys looking to lower their car and track it, or just ride more like a stiff track car. The two are very comparable. The B8’s are setup stiff at the factory. It has no user settings. The Koni Yellow Sports have that advantage of user adjustability to fine tune how the dampers will react whether on the street or on varying tracks. The same analogy holds for coilovers. A particular coilover may be comfortable compared to other coilovers, but can’t compare the the Koni Special Actives on rough roads. Hope this helps! |
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01-16-2023, 05:48 PM | #22 | |
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I totally get that half the job would be done without the RFs but it’s not an option right now for me. So im looking to find other areas where I can make some ground on the comfort. im leaning towards the Koni for comfort due to the info here and research I’ve done so far. I’ve seen a few places that for Comfort particularly the Konis are the ones to go for in this Bilstein/Koni price range. Along with this it would make sense to fit with new springs, I don’t want shorter ones as Koni require the springs to be the OE ones. In my case would be the m sport suspension springs. The ones from the dealer are way overpriced and the aftermarket ones it’s very difficult to tell if they are the same sizing or not. You refer to sachs, are they the OEM for BMW springs by any chance too? I could check those out if I can get a spring partner number from the dealer. Realoem doesn’t have the numbers for springs for some reason. Also I want to ask a favour, in the diagram above can you point out the numbers relating to the parts you mention one should would replace while at the dampers “replace all rubber bushings and mounts including the top hats front and rear. ” |
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