[FaRKle!]

Originally Posted by xpro

I have the same question.

The online catalogue list E10-20-031-05-22 part for 340ix/330dx/335dx.
The Eibach PDF list E10-20-031-06-22 part for the same 340ix/330dx/335dx.

The difference in those springs are the spring height and the payload.

I'm unsure now which is the correct spring for my 16' 335xd



You can see the 05-22 is 35mm/25mm drop and the 06-22 is 20mm/15mm drop

Originally Posted by xpro

The reason I'm confused is that when I rang Eibach they said to go with 06 as the they are a bit stronger due to 1095kg payload vs 1050kg on the 05's.

The combo i'm going with is Bilsteins B6 with either Eibachs but The Bilstein recommends max drop on the B6's is 30mm, which is why I think the 06 might be more suitable.

Has anyone got a photo of the Eibachs 06 fitted? The photo in the previous post is with the 05's and they look totally sick, altough very similar to ACS springs.

Judging by what people say about ACS springs being a bit lower then Eibachs, more I think is they might be based on the 05 eibach model.

The load rating on the -06 is higher because load rating is weight for a specific (minimum) ride height (which will be the same for both springs). Since the -06 and -05 springs have the same spring rate, they have the same strength, however, since the -06 is longer, it takes more weight to reach the minimum height.

I have a B6-based strut up front right now, and with the -05 spring on a 4cyl front I'm already contacting the bump stop at static ride height. The B6 has a pretty soft bump stop, so it's not uncomfortably boosting the spring rate quickly. As I said prior, the longer -06 spring will be more comfortable.

[henkinc]

I have to say I admire you guys who want the perfect look, but for me I prefer the best ride/handling improvement with my adaptive suspension. Either look is fine. One of you said the Eibach ride was almost as the OEM but handling much improved. I am losing the bubble now if that was on an adaptive or non-adaptive suspension.
Again, the notion of progressive springs is appealing since they should maintain nice ride over small deflections but tighten up to stop wallowing under load. But the devil is in the details on compatibility with shocks. And the Dinan modified bump stop also makes a lot of sense for any lowering spring. Has anyone tried the Dinan bump stops with Eibach or other non Dinan performance springs?

[johnung]

Originally Posted by henkinc

I have to say I admire you guys who want the perfect look, but for me I prefer the best ride/handling improvement with my adaptive suspension. Either look is fine. One of you said the Eibach ride was almost as the OEM but handling much improved. I am losing the bubble now if that was on an adaptive or non-adaptive suspension.
Again, the notion of progressive springs is appealing since they should maintain nice ride over small deflections but tighten up to stop wallowing under load. But the devil is in the details on compatibility with shocks. And the Dinan modified bump stop also makes a lot of sense for any lowering spring. Has anyone tried the Dinan bump stops with Eibach or other non Dinan performance springs?

In my pre-purchase research, Dinan had me all wound up about the bump stop issue. Depending on configuration sometimes it's a valid argument, and sometimes not. Of course Dinan wants to sell BMW bump stops (from other model BMWs) that are highly marked up and high profit for Dinan. They kept insisting that I needed them for my final configuration.

My car is a 2015 335i xDrive non-adaptive suspension. I went with the Eibach -06 Spring kit that drops F 0.8", R 0.6". I chose Koni Special Active dampers kit designed for xDrive and tested by Koni with my Eibach springs. Koni insisted that the Eibach drop was mild and did not require shorter bump stops. I mean Koni manufactures the shocks so they should know. They said that if any bump stop modification was necessary then it would be written in instructions included with their damper product.

Koni said that the Eibach springs are about 10% stiffer than stock. Dinan claims a 0.75" drop all around with their spring kit, and claims that theirs are 30% stiffer than stock. I'm not sure how stiff the Eibach -05 springs are with the greater drop? But I was told that the H&R springs with the 1.5" drop are much stiffer than the Dinans.
Hope this helps!

[xpro]

Originally Posted by FaRKle!

The load rating on the -06 is higher because load rating is weight for a specific (minimum) ride height (which will be the same for both springs). Since the -06 and -05 springs have the same spring rate, they have the same strength, however, since the -06 is longer, it takes more weight to reach the minimum height.

I have a B6-based strut up front right now, and with the -05 spring on a 4cyl front I'm already contacting the bump stop at static ride height. The B6 has a pretty soft bump stop, so it's not uncomfortably boosting the spring rate quickly. As I said prior, the longer -06 spring will be more comfortable.

Thanks for the advice. You defo did your homework when it comes to suspension!

So would you recommend me the -06 for my 335xd with B6 combo?
Or have you had any experience with ACS springs? Makes me think since they are lower the -06’s, that they might be based on -05’s?
Thanks

[FaRKle!]

Originally Posted by xpro

Thanks for the advice. You defo did your homework when it comes to suspension!

So would you recommend me the -06 for my 335xd with B6 combo?
Or have you had any experience with ACS springs? Makes me think since they are lower the -06’s, that they might be based on -05’s?
Thanks

If you want a low/dropped look get the -05. If you want a moderate drop, with the better body control of stiffer springs, while trying to maintain as much ride comfort as possible get the -06.

ACS springs are just rebranded Eibachs for the F3x (and their kits seem to be based upon the older revision of Eibach spring kits). There's literally no difference other than the brand stamped on the spring.

You can look through my previous posts to look at the documentation that shows it.

Originally Posted by FaRKle!

ACS springs are just Eibach springs. If you look at ACS' TUV documentation (from their website) they list things like # of coils, active coils, wire diameter, and spring length. Match that with the Eibach spring in Eibach's TUV doc and look at the specs/drawings/properties/test data there to see what your ACS has.

From what I recall (you'll need to verify), ACS uses Eibach's F34 (3-GT) rear springs for their F31 kits. That spring has a higher overall load rating, but I don't think it's as long, which likely leads to the reverse rake.

Also, I had my OE F31 rear spring compared to my Eibach F31 rear spring at my suspension guru's today and they have about the same spring rate. My suspension guy said that's not too uncommon where a lowering spring company will only stiffen the front rate.

Originally Posted by FaRKle!

It seems that ACS has pulled the individual spring PNs from the product pages (they only give you the kit PN now). They've also disabled the "documents" tab on the product pages with the link to their TUV testing. I guess they didn't like people like me (and these guys) looking at the data and finding out they're just rebranding Eibach springs.

The individual spring PNs can still be found easily enough on their retailers' sites if you search the kit PNs.

BTW, here's the link to their TUV documentation for the 1/2 series. Likely some of the PNs are the same as the fronts for the 3-series.

*EDIT* re-found the ACS 3-series TUV documentation.

[rphz]

Originally Posted by johnung

My car is a 2015 335i xDrive non-adaptive suspension. I went with the Eibach -06 Spring kit that drops F 0.8", R 0.6". I chose Koni Special Active dampers kit designed for xDrive and tested by Koni with my Eibach springs. Koni insisted that the Eibach drop was mild and did not require shorter bump stops. I mean Koni manufactures the shocks so they should know. They said that if any bump stop modification was necessary then it would be written in instructions included with their damper product.

I'm looking to do something very similar and was curious how you rate the overall ride quality with the Eibach/Koni combo compared to stock? Any complaints with this setup, and do you think you should have done the shorter bump stops or is this not an issue for you?

I've been lurking in this thread for awhile now and really appreciate all of the info you (and FaRKle!) have posted about the Eibach springs

[johnung]

Originally Posted by rphz

I'm looking to do something very similar and was curious how you rate the overall ride quality with the Eibach/Koni combo compared to stock? Any complaints with this setup, and do you think you should have done the shorter bump stops or is this not an issue for you?

I've been lurking in this thread for awhile now and really appreciate all of the info you (and FaRKle!) have posted about the Eibach springs

I'm glad that you found the information helpful. I gotta meet that FaRKle! guy someday! I've been driving the Eibach springs/Koni Active dampers combo for about 9 months now. They have exceeded my expectations. I wanted to tighten up the suspension without adding more harshness.

This is long winded but I thought it might help to give some insight into my thought process along the way. Everyone has their own priorities when it comes to modifying their car and that gets them to different solutions. That's why this car stuff is so much fun!

The Suspension Goals:
I've done mods in the past with other cars. Adding sport suspension components usually involves that type of trade-off. Great handling cars usually don't handle bad roads too well. This is a family daily driver. I wanted a car that is both comfortable on family trips and really fun when I'm driving by myself, hitting that curve in the road.

Picking the right sports sedan!
My wife and I went through a process in looking for right used car for us. (First fun car after decades of many kids, minivans and big SUVs.) She had already driven a Lexus for years with a comfortable highway ride that had nothing in the corners. Mercedes had some attraction because they take that smoothness in a much more German car direction. IMO Mercedes approach still isn't the right mix for a sports sedan. The stock 335i x-drive was much closer to the ultimate (driving machine! Had to say it!) It was actually my wife's eyes that lit up when she drove the 335ix. I never thought that she'd go that sporty so I didn't think to suggest. I was pleasantly wrong!

How the 335ix suspension might be improved to fit our needs
After driving our "new" used car for a few months I got a sense for the drawbacks of the stock suspension. The difficulty was that the issues are on opposite ends of the spectrum. We live in the Northeast. The stock suspension had a teeth rattling aspect to it when you hit rough roads and potholes. Got the car in December and set a goal of modifying the suspension before leaving in July on a 3,000 mile road trip with my son to visit a dozen potential colleges. I was afraid of losing my mind on a long trip because of how poorly the stock suspension handled road seams....endless jarring bump...bump...bump.

On the other side of things, that harshness wasn't even a compromise that had resulted in great handling. Even with xDrive, the suspension of the stock car just didn't handle curves well. The car understeered with a lot of body roll. Bottom line: It could be so much better, so much more fun!

Initial Assumptions
When I began my search, I honestly expected to discover that the compromise that I hoped for didn't exist. I thought that I would have to follow the typical scenarios to get better handling, most of which in my past experience take away, at least a bit, from the ride comfort. Early on I would have bet that my final solution would have been dampers from say Bilstein or Koni, at the milder end of their sport shocks, i.e. Koni adjustable yellows. A mild drop spring set like the Dinan at 0.75" was a good possibility too. I spent a lot of time investigating coilovers but costly and lots of divergent opinions. Very much a more sporty direction than our goals and could spend that money better on other priorities.

New Damper Technology
In researching the Bilstein and Koni products I spotted the Koni FSD technology. I took it with a grain of salt. I've spent most of my career in a technical industry at the forefront of technology. There was a lot of sorting through marketing materials to figure out what was a real breakthrough that could actually be implemented and the other 80% that was mostly marketing B.S. Koni developed this technology with McLaren and the science seemed sound. The more I researched, the more solid it appeared to be. I read many actual user comments from Europe because Koni hadn't really been marketing the technology at that point to end users in the U.S.

Eibach's Great Reputation
What clinched it for me were many conversations and emails that I had with the top Koni technical guy who was very credible and answered every question that I had over a couple of months. That's how I learned about Koni North America having actually tested their xDrive Special Active dampers with the Eibach spring set. I did research on Eibach at that point too and learned how solid they are.

Use Stock Bump Stops in this Configuration
Koni's technical guy is also the person that insisted that no bump stop changes were necessary. That was based on actual testing with a shock that hadn't been released yet so I took his opinion over a Dinan sales guy that was trying to sell bump stops for a shock that he had never seen or sold. (It's another long story but the first set of the Koni Special Actives on a 335ix customer car in the US went on my car.) So my suspension was installed with unmodified stock bump stops. Based on my driving experience, Koni was correct about the stock bump stops being fine in this combination.

Other Suspension Mods: Sway Bars
A suspension is the sum of its many parts working together. I've already posted about my belief in sway bars to combat body roll in corners. Labor is expensive to install sway bars on the F30 but the H&R sway bar upgrades on my car make it corner flat!

Don't Forget a Key Component: Tires!
Another key component of the suspension are the tires. Big thanks to alohasurftoad and his great advice on wheels and tires. BMW gave me my first experience with runflats. For over a year I was steadfast in wanting to stay with runflats and just upgrade to the best one that I could find. A month ago I changed my mind and am so glad that I did. (I made separate posts about the kit that I now carry in my car in case of a flat.) I decided to save the tread on my existing runflats to use next winter.

With our Hawaiian guru's help I made two tire changes:

1) Upgraded from runflat tires to the best possible summer tire, the Michelin Pilot Sport 4S.
2) Upgraded from the stock square 225/45-18 size, to the wider and better handling 245/40-18.

This tire upgrade was as dramatic of a suspension change as my shock/springs/sways upgrade. The new tires make it seem like the previous runflat tires were wooden wagon wheels. The car now sticks to a curve like glue. The other day I drove it on I-95 and some horrible roads in the middle of Philadelphia. The suspension has evolved tremendously. It now handles rough roads and road seams like a luxury Lexus and handles high speed on-ramps and off-ramps like an open wheeled race car. The Michelin PS4S has an outside tread that you can actually feel grip the asphalt as soon as you turn the wheel into a curve. Just amazing!

The last piece to my suspension mods will return from powder coating next week for installation. It's a front shock tower brace. I'll post about that later.

I've written a book, or at least a short story, as usual. Hope this is all helpful to someone, down the road! Fun With Cars!

[henkinc]

Hope I got your name correct!
First, Dinan bump stops are not just some marketing BS as far as I can tell. If you check them out, they are unique in that they incorporate springs at the top of the strop so that the "bump' is progressive. Seems useful for a drop in spring length of even 3/4 inch. Perhaps the bump stop is really needed when combined with a non progressive spring, such as Dinan sells for the F30.

I am really interested in how the Eibach progressive spring works with the stock BMW shocks, however, since I have adaptive suspension on my 335Xi and hate to get rid of it. Any idea how the shocks in your 335Xi with non adaptive suspension compared to the adaptive shocks? I hear in this thread that Koni is coming out with an F30 adaptive shock offering and wonder how it mates to the adaptive shock system in the 335 Xi. I believe the adaptive shocks are magnetic rheological (like Corvette/Cadillac) so the electronic settings might be unigue for the shocks BMW installs. Hence how would Koni work out?

I also feel the chassis is not quite as stiff as I would like, particularly with the cornering I have with Michelin AS3+ all season rubber (HATE my old run flats!). Can you send pix of the installation and a report on whether the strut bar really helps the car?

Thanks for the detailed reporting.
Charlie

[henkinc]

I guess by M-suspension they mean adaptive. Anyway, not offered for my car it seems, based on the Koni web site..

[johnung]

Originally Posted by henkinc

Hope I got your name correct!
First, Dinan bump stops are not just some marketing BS as far as I can tell. If you check them out, they are unique in that they incorporate springs at the top of the strop so that the "bump' is progressive. Seems useful for a drop in spring length of even 3/4 inch. Perhaps the bump stop is really needed when combined with a non progressive spring, such as Dinan sells for the F30.

I am really interested in how the Eibach progressive spring works with the stock BMW shocks, however, since I have adaptive suspension on my 335Xi and hate to get rid of it. Any idea how the shocks in your 335Xi with non adaptive suspension compared to the adaptive shocks? I hear in this thread that Koni is coming out with an F30 adaptive shock offering and wonder how it mates to the adaptive shock system in the 335 Xi. I believe the adaptive shocks are magnetic rheological (like Corvette/Cadillac) so the electronic settings might be unigue for the shocks BMW installs. Hence how would Koni work out?

I also feel the chassis is not quite as stiff as I would like, particularly with the cornering I have with Michelin AS3+ all season rubber (HATE my old run flats!). Can you send pix of the installation and a report on whether the strut bar really helps the car?

Thanks for the detailed reporting.
Charlie

The bump stop concept is a good one. I just didn't agree with them telling me that I needed their bump stop when the damper manufacturer said that I didn't. They are just marking up bump stops from other BMW models. Wish someone with access to a BMW parts bin would snap photos of bump stops with measurements and part numbers.

I don't know anything about adaptive dampers. I wouldn't touch them. If you want to add lowering springs check out threads from the guys who have done it.

I plan to post about the shock tower brace after it comes back from powder coating over that shiny aluminum finish that didn't look very good under the BMW hood.

[FaRKle!]

All of the bump stops (OE and "Dinan") should be thought of as secondary springs. When the car/damper are loaded into them that's how they act, as stiffer springs. Some have linear spring rates, and others (conical in shape like our OE rear ones) have progressive spring rates. Therefore, how soft/hard a bump stop is should absolutely be considered when using/changing them as it will affect how the transition feels once they start getting loaded

Damper travel before bump stop engagement is also important to know. If you have relatively soft springs, but a hard bump stop, the transition will feel more abrupt and less smooth once the bump stop starts to get loaded. When testing how much damper travel I had before bump stop engagement I realized that for the rears, I was sitting on the OE bump stop at static ride height (with my Eibach springs). The F3x OE rear bump stop is 3.5" in length, fairly hard, and progressive. The E60/"Dinan" rear bump stop is 2.5" in length, and softer. Switching from the OE one to the E60 improved my rear ride comfort when hitting bumps due to more damper travel before engagement, and also a smoother transition between the rear spring and the bump stop.

Bump stops basically turn your linear springs into progressive ones, once they engage. Some vehicles are meant to ride on the bump stops very early on and that's how the mfg controls body movements (such as reducing body roll). Those are typically progressive in nature, and don't have quite as stiff of an initial engagement.

[rphz]

Originally Posted by johnung

I've written a book, or at least a short story, as usual. Hope this is all helpful to someone, down the road! Fun With Cars!

Really appreciate the write-up and all of the detailed info as it's very helpful! And thanks for being a guinea pig with this combo for the rest of us

[johnung]

Originally Posted by FaRKle!

All of the bump stops (OE and "Dinan") should be thought of as secondary springs. When the car/damper are loaded into them that's how they act, as stiffer springs. Some have linear spring rates, and others (conical in shape like our OE rear ones) have progressive spring rates. Therefore, how soft/hard a bump stop is should absolutely be considered when using/changing them as it will affect how the transition feels once they start getting loaded

Damper travel before bump stop engagement is also important to know. If you have relatively soft springs, but a hard bump stop, the transition will feel more abrupt and less smooth once the bump stop starts to get loaded. When testing how much damper travel I had before bump stop engagement I realized that for the rears, I was sitting on the OE bump stop at static ride height (with my Eibach springs). The F3x OE rear bump stop is 3.5" in length, fairly hard, and progressive. The E60/"Dinan" rear bump stop is 2.5" in length, and softer. Switching from the OE one to the E60 improved my rear ride comfort when hitting bumps due to more damper travel before engagement, and also a smoother transition between the rear spring and the bump stop.

Bump stops basically turn your linear springs into progressive ones, once they engage. Some vehicles are meant to ride on the bump stops very early on and that's how the mfg controls body movements (such as reducing body roll). Those are typically progressive in nature, and don't have quite as stiff of an initial engagement.

Great stuff! Thanks for the info!
What happened with your front struts as far as the bump stops?

[FaRKle!]

Originally Posted by johnung

Great stuff! Thanks for the info!
What happened with your front struts as far as the bump stops?

The Bilstein B6's I have up front (and all Bilstein mono-tube struts for the F3x platform) have internal bump stops at the bottom of the strut. You need to unscrew the nut from the bottom of the strut, then unthread the shock out of the strut to get to them. They're about 2.5" in length, and the ones in the B6 are pretty soft (definitely softer than OE).

At my static ride height I was already compressing them .5", however, since they're so soft it wasn't very noticeable. Just for the sake of it though, I trimmed them .5".

[/Angelo/]

I pored over this and other similar threads and I'd like to thank everyone for their input. Without getting into the weeds, our F30 is my 2-year old son's primary means of conveyance, so it was important to focus on safety and driveability as opposed to outright performance. I wanted a conservative drop with stiffer dampening so I went with Eibach springs and Bilstein B8 shocks. The front springs could be a little lower, but we're still satisfied with the results.

On a side, the OEM brakes are effective but laughably puny. M Performance brakes coming soon. You know, for safety and all that .

[xpro]

So basically from my understanding on the Eibach springs, some people are happy with the drop and some arent.

Since there are 2 models listed fro 335/340 xdrive, although identical springs but one drops more them the other,which would explain why some people are not getting the drop they expected and some do.


E10-20-031-06-22 ( 20mm front and 15mm rear drop)

E10-20-031-05-22 ( 35mm front and 25mm rear drop)

As many have said they were not overly happy with Eibach drop, I would guess they went with the 06-22 part number..

[johnung]

Originally Posted by xpro

So basically from my understanding on the Eibach springs, some people are happy with the drop and some arent.

Since there are 2 models listed fro 335/340 xdrive, although identical springs but one drops more them the other,which would explain why some people are not getting the drop they expected and some do.


E10-20-031-06-22 ( 20mm front and 15mm rear drop)

E10-20-031-05-22 ( 35mm front and 25mm rear drop)

As many have said they were not overly happy with Eibach drop, I would guess they went with the 06-22 part number..

The Eibach -06 part number is meant for xdrive models. I installed them on my xdrive and got the predicted drop.

Drop it more and then other issues come into play starting with whatever dampers being used having enough travel, the bump stop shaving or swapping out, etc. etc.

[xpro]

Originally Posted by johnung

The Eibach -06 part number is meant for xdrive models. I installed them on my xdrive and got the predicted drop.

Drop it more and then other issues come into play starting with whatever dampers being used having enough travel, the bump stop shaving or swapping out, etc. etc.

Do you mind posting some pics with the -06 please?

The other strange thing is that 05-, and -06 kit have 15mm different length front springs, while the rear springs are identical in both kits!

[Kaps335i]

I ended up doing the Koni Special Active and Dinan sway bars. Very nice difference over stock and little body roll. Slightly stiffer springs would probably be nice, but I didn't want to lower the car.

[dsc888]

Originally Posted by mark_tdot

Lowered my xdrive on eibach's last week.

I used the RWD version though - part no. E10-20-031-02-22

Absolutely beautiful drop and ride!

How has your xDrive been riding since the drop? I'm in Boston and have snow to deal with like you up north but want to get the 05-22 kit (35mm front and 25mm back) for a more even drop front and back and also have the MPerformance front splitter like you and do worry about the snow.

I'm also guessing I will need to get a new "low profile" jack as well if I go low. My current 3 ton Harbor Freight standard jack might get caught up on the side sills once lowered.

I appreciate any feedback you may have!

[dsc888]

Originally Posted by johnung

I'm glad that you found the information helpful. I gotta meet that FaRKle! guy someday! I've been driving the Eibach springs/Koni Active dampers combo for about 9 months now. They have exceeded my expectations. I wanted to tighten up the suspension without adding more harshness.

I researched the Koni Special Active shocks and am considering them as a close option to the Bilstein B8s. I do like the idea of a compliant ride when not driving aggressively. Interestingly enough, Bimmerworld's website stated that they are NOT meant to be used with lowering springs! But it seems you have been fine with them with your Eibachs, which I will also get for my xDrive. Koni's own site states that the Special Actives can be used with Sport Springs.

[johnung]

Originally Posted by dsc888

I researched the Koni Special Active shocks and am considering them as a close option to the Bilstein B8s. I do like the idea of a compliant ride when not driving aggressively. Interestingly enough, Bimmerworld's website stated that they are NOT meant to be used with lowering springs! But it seems you have been fine with them with your Eibachs, which I will also get for my xDrive. Koni's own site states that the Special Actives can be used with Sport Springs.

During my decision process I actually spoke to the top technical guy at KoniNA. It appeared that the Special Active dampers for xdrive were not designed for normal drop springs like the H&R springs that drop 1.5". This is because it would shorten the damper piston travel too much. They didn't include mild drop springs like Eibach (part# -06) or the Dinan 3/4" drop springs.

The Eibach springs and Koni SA dampers work great together on the xdrive.