Why Bilstein B6/B8s Change Your Ride Height 

Do you happen to know if you can use sport springs on the B6? Why or why not? For e93

I’m American and I don’t even know what that means lol. Metric is the way to go

@@dumbeezy5480 it means 32” and 5/16ths

You are just dumb

From a guy who would say it’s 15.3 degrees outside 😆

@@dumbeezy5480 you are just naturally dumb

I don’t have a Mercedes’ but my S4 is in need of new shocks and I wonder what I should go with. I mainly commute in this vehicle , no track days here.

@@vocalone23 nothing wrong w/OEM (except price). You'd be amazed what new parts do. I put regular B4 Touring Bilstein (black body) on my 13yo GTI and the car felt solid and more composed. Bushing changes and sway bar changes can firm things up to and not be as harsh as an actual spring/damper change. Look for uprated street (not race) mounts/bushings [034 Motorsports comes to mind], replace shcks/strts w/OE equivalent and then look into stiffer sways and you'll have a firmer, sportier ride with near OEM ride manners. Coilovers are an option, but not if you live in the snow belt and you will only realize their true benefits if you corner balance. Coilovers get misused all the time by ppl using them just to go low. That's not what they are meant for. They are meant to change the weight balance of the car for better handling/cornering. Good tires and alignment help too.

Right! Born American, but I work on mostly German (MB) cars as hobby and career is in medicine, so pretty much all I use is metric and I have no idea what any of the 5/8, 7/16, 1/32 crap is. I couldn't even guess the size unless it's obvious like 1/2 or 3/4.

I'm a born and raised Utahn and I'm 100% with you, at least in measurements of length anyway. This may help yuh, 12mm is close to 1/2 Inch (1 half inch) 1inch is about 25mm, 3 inches is about 75mm, 150mm is about 6 inches and 200mm is close to 8 inches everything else falls in between these. If I get lost on mm I use this website... www.engineeringtoolbox.com/inches-mm-conversion-d_751.html Hope this helps.

Best part is, ISO uses metric to calibrate their imperial systems

I'm from the UK and it makes sense, it's just fractions. but then i grew up when everything was being switched over when it came to measurements so i know roughly the lengths in different measurements but no idea how to convert them haha but that's what google is for

It means 7 inches long with an extra13 parts of 32 of an inch 😂ha ha ha.. you. 👉😵

I have Koni Special Actives and they did not change ride height at all. I am meticulous about before and after chassis height measurements so I know this to be an accurate statement.

The b8’s are designed for a aftermarket lowering spring not the B6’s shown.

There are couple of issues with the belief that B6/8 are designed for Eibach Pro-Kit springs (aka B12 kit). 1) Bilstein uses the same B6/8 PN no matter which F2x/F3x car you have (divided into RWD and xDrive). 2) Eibach spring rates differ depending on the model of F3x/F3x you have. 3) Pre-load is irrelevant since the static ride height is determined by the vehicle weight, unless the droop of the damper is limiting things such that it compresses the spring greater than the weight of the car would (but that's not the case). 4) I've dyno'd B6 dampers, seen the Eibach spring specs, and know that these dampers are overdamped for the Eibach springs.

FaRKle0079 I don’t have an F body BMW and am not overly familiar with their suspension layout to begin with, but I am a chassis design engineer and I literally do this for a living. The B6 will work with the factory length spring fine but the B8 needs a shorter spring to function correctly. If B8 dampers get fitted with the long BMW factory springs, you’ll have to pre-compress them a lot to get the top plates on - thus the assembly has increased preload, and the damper’s stroke length is compromised because the car rides higher than it should. It’s also worth pointing out that the eibach springs progressive coil pitch matches with the flatter mount plate, meaning they don’t sit at an angle. Why did you slap a B6 on a damper dyno? We tend to do that kind of work when we’re making custom damping rates, or to check if a damper is shot after a big impact....

​@@mattrolls618 BMW uses a large variety of springs on the F2x/F3x vehicles (~30 for the fronts alone), and the lengths of these springs varies. Some of these springs are very close to aftermarket springs' rates and lengths. For example instead of getting the Eibach kit for a 330i, you might instead grab a set of M3 springs which end up having the same spring rate and length (this isn't specifically the case for the models in the example, but it is a real life case between various models). For the BMW F2x/F3x chassis vehicles Bilstein advertises the B6 for use with OE springs. The B8 for these vehicles uses the same strut body, but has a slightly different damper cartridge where the piston shaft and bump stop are shorter to accommodate springs that sit lower at static ride height (the valving is the same though). Both B6 and B8 require spring compression to get the top mounts on, so yes there will be different preloads at full droop, but this platform should very rarely experience full droop during driving, and at static ride height the front springs and dampers are compressed quite a bit. I agree that it's important to understand the amount of damper travel you have, but with both B6 and B8 you're much closer to hitting the fully compressed travel limit, than the droop limit. Of course that means you'll be riding your bump stops all the time. I agree with you that the end coils of Eibach springs' (and aftermarket springs in general) don't necessarily conform to the reference OE springs' design (probably because they don't have the drawings). I dyno'd the B6 because I ended up using them as a donor set for custom damping rates. I took a look at the internals of these damper cartridges during that activity. On a more "end user" level I also compared a B14 strut to this B6 one in this video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-tIfh1MnXtiI.html

In my experience working with Eibach springs across a variety of vehicles, I wouldn't consider the vast majority 'matched' to the dampers. I'd say it's a combination of non-optimized damping and often a choice of spring rates that creates pitch instead of Flat Ride (as OEMs usually oft for). I appreciate the work Andrew is doing to show specific cases when springs supplied on an aftermarket setup are far from ideal for ride or handling, and that the damping has much room for improvement. There are cases when the B8 and B6 have different damping, but generally the differences are small. The point to clarify on where a B8 is shorter is on the damper shaft stroke, usually 20mm less on a B8. This is achieved via added droop spacer inside the damper body. The strut or shock body lengths between B6 and B8 (for all the cases I've seen) are the same.

I have bilstein b6 all around with eibach pro kit springs on my 2003 e46 318ci. Sits nice . Not too low . The ride is very firm and stiff and I can push the car in turns way more ! 205/55/16 91V Michelin primacy 4 tires ! Style 45 rims .

They physically fit each other, but BMW has different damping forces corresponding to the different weights. I'd look for the appropriate one for your vehicle.

Just about 1/2" all around. I measure from center of the wheel/hub to the fender, which is consistent no matter what size wheel you have.

When did you measure? A few days after installation or did you let the shocks break in for a few weeks?

@@FaRKle0079 Saw a post of someone claiming their B8’s settled after a few weeks and it was no longer as high. Was this your experience?

@@rayland9305 I think that was more due to their bushings taking a new set. The gas force shouldn't lower enough to cause that in just a few weeks (or you'd have a leak).

Bilsteins will be higher damped than the stock shocks. If you prefer more "road feel" and are willing to sacrifice some comfort they can be a good option.

You should be able to read the part number off of the sticker on the side of the shock to find out if it's a B6 or B8. B8 should be shorter than a non M-sport shock.

You can use either. If you're lowering a half inch or more from M-Sport, I'd go for B8s though.

For this F3x platfrom around 4-8mm.

FaRKle0079 ok thank you , I have a 2019 F20 m140i , will it be the same with this car , I’m fitting Eibach Pro springs to the b6 damptronics and don’t want the front too low , thanks again 👍

@@FaRKle0079 Aahhhh fresh millimetres

How much is considered “lowered” ? I have h&r springs and my vehicle drops 1.75inches in the front and 1.50inches in the rear. They currently don’t make a B8 for my application so would i be good with just B6??

Simply Built_ Maybe it’ll do, but you have chances of shorter lifespan because the shock is outside of it’s designed range. Give Bilstein a call is my suggestion.

So how does the measurement between base(or stock) ride height and sport suspension fit in?

I have the M Sport springs which are -1.5cm from base versions. Do I need B6 or B8?

@@dkib2006 B6 yes, from like -3,5 and under take B8

The Bilstein dampers and Eibach lowering springs should lower your ride, but not as much as the same lowering springs on stock dampers.

With either the B6 or B8 you'll probably want to go to stiffer springs. So if the options are stock springs with B8 or B6 with Eibach springs, I'd probably opt for the second combo.

They'll be less comfortable over smaller features (feel more of the road), but will have a lot more body control.

Are they still working good?

Stay away from B6 if you are using lowering springs . It will raise your car slightly i regretted it . Use OEM B4 sport if its a slight drop like 1 inch or 1 - 1/4 .

B4s tend to be twin-tube and not monotube like B6/8. I can't say I'm familiar with the differences between the regular and sport versions, but the sport version likely has a lot more rebound.

@@FaRKle0079 more rebound equals a stiffer ride right?

@@EJR20 If you don't have a good amount of free damper travel before the bump stops, yes. It also depends on the spring rate and corner weight, but that takes more work to figure out if it's appropriately damped, or over damped.

Yes, stock springs will work with B8. They'll be overdamped though.

Either B6 or B8 will work for that. B6 work fine for lower if you shorten the internal bump stops on the struts.

@@FaRKle0079 B8 it is then haha. There was someone else on a forum who has reported that either B6 or B8 will every so slightly increase the height the car. B6 more than the B8.

There's no need to zero the ICM ride height with a passive damper. It also didn't seem to actually do anything when I changed heights on my adaptive dampers.

B6s should pair decently with Dinan springs since they're a good bit stiffer than stock. Overall you'll still feel more of the road texture due to the higher gas forces, but ride should be decent.

@@FaRKle0079 Sounds good, thank you.

Do you happen to know if you can use sport springs on the B6? Why or why not? For e93

The previous dampers I had were still very healthy (I dyno'd them). The gas force on the Bilsteins is high, and acts like an additional spring propping the car up. Either way, the damper shouldn't really be holding the car up, as that's the springs' job.

@@FaRKle0079 Aren't bilstein made more for offroad, where a little extra stiffness is always appreciated or wanted?

@@jpegjake Bilstein makes a wide range of dampers focused in different segments. For a sportier car like the BMW 2/3/4 series, an offroad damper might not make much sense. The B6/B8 for this platform are definitely road focused.

Ride quality is definitely more harsh with B8 due to the overdamping and higher gas pressure. The higher gas pressure means you have that much more force to overcome before the damper starts to move, so if before that the damper acts like a solid rod. This is most noticeable on small textures in the road. Being overdamped doesn't let the suspension move/soak up as much. Going to stiffer springs is better for an overdamped system because then you're reducing the damping factor. Of course there's a point at which you go too stiff and the springs have less isolation, but something like Eibach is fine. Also, check your bump stops. A lot of times when lowering you're sitting on the bump stops, and that transmits a lot of harshness.

@@FaRKle0079 i asked around most of b8 user pair them with eibach since h&r is a ton more stiffer.i already check the bump stop even to the point cutting them to a shorter length but still the ride was hell. My last resort is try to pair it with eibach springs or just sell it and sticks with avantgarde shocks im using now.slightly stiffer but doesnt rattles ur insides. Now i wish i've gotten those coilover kits. Less hassle and an peace of mind.tq sir. Any other suggestions? I've check my b8 no leaks nothing.

@@kurt_styloe Since the B8s have such high damping force, going to even stiffer springs can make them feel more comfortable because the overall damping ratio goes down. The B8 fronts should handle springs up to the 225lbs/in range just fine, and in the rear you can go way up there (like 800-1000lbs/in) without being underdamped.

@@FaRKle0079 noted sir.thnx for the headsup. Guess i shud invest in lowering springs...😅

That's within the range of their stroke. Probably still overdamped like they usually are.

@@FaRKle0079 if so, what effect would have on driving? Overdamp will affect durability according to you? Thanks.

@@OritanoVero Overdamping doesn't affect durability. It'll make the car feel like it has more body control, but also make the ride more harsh.

B6 will be fine with your stock springs. If you decide to lower later with Eibach/Dinan/ect. grab a set of B8s for better bump stop clearance. These are higher damped than OE replacements. Better if you want to go to stiffer spring rates later, but will be less comfortable too.

@@FaRKle0079 hows the B6 comfort compare to stock? Did you have both b6 and b8?

@@kennypham8585 I didn't use the B6/8 since I had them revalved by FCM. That said, they should be less comfortable than stock since they're higher damped and have higher gas force. The tradeoff is they should have better body control.

@@FaRKle0079 I see. But it’s not super uncomfortable though right? if so then I don’t think I would get them

@@FaRKle0079 you live any where near garden grove Cali?

You might want to check the amount of travel you have before the bump stops engage. A lot of folks that lower their cars feel like they bottom out more because the bump stops engage sooner. Replacing the bump stops with shorter ones or shortening the existing ones typically helps with this,.

@@FaRKle0079 Thanks for your recommendation. Mine is at stock hihgt though but I will look if I can find shorter ones either way.

B8 are meant to be used with aftermarket springs ie: Lower spings, B6 is meant to be used with stock springs. B4 = OEM level B6 = a bit sporty & firm, to be used with stock springs B8 = as B6, but shorter and meant for use with sport/lowering springs B12 Pro-Kit = actually a kit that consists of B8 + eibach pro-kit springs, mild lowering B12 Sportline = as above but even lower (eibach sportline springs, or maybe H&R) B14 PSS = entry level coilovers B16 PSS9 = coilovers with damping adjustment and etc.. Bilstein did not ruin your car, you did with incorrect application.

@@lanceivor Thanks for the explanation. And youre rigth, my wrong decision ruined my drive. I will unpgrade to B6's soon.

Yes, Bilstein B6/8 typically make the ride rougher compared to stock due to the higher gas pressure and damping.

Yes.

@@FaRKle0079 I'm going to disagree with you on this video. There is physically no way that a shock/strut will change the ride height of your car unless the part is completely wrong, i.e., an E65 shock on an E90, where the part is considerably longer and the car sits on the part completely compressed and is bottomed out. Springs dictate the ride height of your car. As for your spring pads, those also contribute. If you are putting B8's, which are specifically designed for lowered cars, then you also need to use the proper spring pad. The minuscule difference on the slight angles of the spring pad seats are of no consequence to where the pad sits and how the spring sits on it considering you are using the proper ones. If you can press down on a B8 with 45 lbs of pressure with your hand to get it to compress, how could you believe a 2-ton car would be held up by it? B6's are for stock ride height, but those are considered HD or heavy duty and B4's (at least when talking about MBZ) are considered OE or touring. Both B4 and B6 are for stock ride height, with B6's being much stiffer and the B8's are for lowered cars and are stiffer than B6s.

@@lsmalley Let's go to the math! Assume the spring is a rectangle that's 90mm wide and 250mm tall free length (these dimensions are very close to BMW F2x/F3x front aftermarket and OE springs). The difference in angle between the Bilstein spring platform and OE platform is 4deg. If you use trig (90*sin(4deg) + 250*cos(4deg)) to get the new height of the rotated rectangle you get an increase of 5.67mm just from the difference in angle alone. Now let's look at the gas force contribution. Let's say there's 30lbs (13.6kg) more gas force on the Bilsteins. That's equivalent to removing 13.6kg from the weight on that corner. We'll say the front corner weight is 380kg in this example (which is accurate for some F2x/F3x models) and assume a spring rate of 30N/mm, which is close to F80 M3 front spring rates. So converting the 380kg and 366.4kg corner weights into forces gives 3727.8N and 3594.384N. Then using Hooke's law we can see the amount of compression on the spring for those weights is 124.26mm and 119.81mm, so another delta of 4.45mm. Add the 4.45mm to the previous height addition of 5.67mm and you get a total of 10.12mm, or 0.398". Right in the 1/4" to 1/2" range I've mentioned.

@@lsmalley For the BMW F2x/F3x chassis Bilstein B6 and B8 are valved the same/have the same damping curves, the only difference is piston shaft length and internal bump stops for the front struts. Bilstein instructs you to reuse the OE BMW spring pad/seat, so there isn't a different one to pick (nor does BMW make others for these chassis).

@@FaRKle0079 I mean you're really going above and beyond right now. In the video and title you're saying that the B6/B8 change your ride height. I'm saying it doesn't. Doesn't matter how many different formulas you try to use to prove a point, it just doesn't add up. www.bilstein.com/us/en/product/bilstein-b8/ You're using the struts wrong. B8s are for lowering springs. Springs dictate ride height.

They're not supposed to, but due to some of the characteristics they have, can.

Which one feel like im riding on clouds?

@@bigstep9276 bags?

The shock shaft is shorter, but the damper body within the strut body is the same length. The strut body is the same as B6 for this BMW platform.

@@FaRKle0079 thanks 🙏

Your right. The higher force to compress the strut is basically macking the spring act stiffer by a couple pounds which the car will not go as low as it was before by a small amount. Also to note the bilstiens have a more faster aggressive rebound force which also adds a little to the effect

Yes, the car in this video is xDrive.

I programmed EDC out of my vehicle so I can run passive setups just fine and without any errors. I can always program it back later.

You can get damptronic versions which are compatible with oem adaptive

@@kals7634 Yup, those weren't available till recently. The B6 damptronics for the F2x/F3x are twin-tube and not monotube, so they probably don't have quite as high of a gas force.

FaRKle0079. Weren’t available for a while due to covid but I believe they’re up and running. According to the blurb on Bilstein web site they’re mono tubes as well. Looking to upgrade mine soon but between B6 and B8. Running ACS springs so lowered a bit

@@kals7634 The damptronics were announced a number of years ago, and then didn't materialize till last year, but even then, stock levels were absolutely atrocious. The B6 damptronics for the F8x are monotube, but the F2x/F3x ones definitely aren't since you can see the solenoid valve on the side of the damper body and the part number pre-fix is the same as Bilstein's other twin-tube dampers.