As asked. I have particular problems with the roll and straight-out stability of my '12 swb airmaitic, so non ABC, wich had a COMPLETE and OEM overhaul of the suspensionsystem. So new struts, new this, new that..everething new, and i mean everething even the rearsub mounts. Steerring rack. Bearings front and rear, you name it. Everething OEM.
Even after all of this...i find the car unstable. Not a lot, but i cant let the hands of the steerring. Got the 20 oem AMG wheels. MO Michelin Pilot Sport front and rear, 255/275. Bin to several sports mechanics, so racecar specialists so it had seen some alignmentspecialists. Steerring is spot on in the middle, car doesnt pull to the right, of left. Its just...its like a old landyacht. Doesnt feel as a stiff staight-on feeling car. Needs corrections on the wheel. And if so done, it feels like the rear is going all places after thát correction. In S its a bit better, almost OK. So the last tuneguy/sportcarmechanic/techguy (you name it, but a servicestaiton where they setsup sportscars) changed the frontlowercontrollarms wich go forward rubber (oilfilled?) bushings with PU bushings. And thát was an e-nor-mous step forward.

Now am at the moment to take the next step. Maybe the rear lower controlarms? Or more in the front? S65 swaybars? I dont know yet, so hence the topic.
Everyboday says "its a S-class so it cant be stable", "buy a Audi or BMW" but im so deep in to it, but due of the costs i've made there's hardly any way back. Plus the looks. These BMW/Audi nowadays..

Thanks in advance. Nice forum BTW.

 

please read it makes sense - for many years I wanted 18" wheels on a car, to me it always looked like the right compromise to give decent room for some brakes, a short sidewall for good steering and handling, but with enough compliance for low noise and decent comfort - plus reasonable styling

but life got in the way as motorbikes do fun far better than a car - so cars took a back seat but I've had in the last 20 years...

2.5 td Vauxhall Omega with 215 x 65 x 15" tyres - (effectively a chevy Lumina), it came as std using the BMW 6 pot, iron block tractor engine - once chipped it was fantastic, a bit sloppy but comfortable and enjoyable, with very exploitable handling

It was replaced with a facelift 3.0 V6 petrol Omega with Xenon's and 225 x 55 x 16" tyres - they re-did the suspension bushing to go with the bigger diameter wheels, but its handling was far worse and aside from the xenon's its was never as good at the earlier one. Even with traction control you had to disable as you soon as you started the car, the lack of mid range grunt meant you couldn't unlock the handling benefits of rear drive.

I replaced that with a 335d BMW twin turbo tractor on std 17" wheels with run flat tyres and no location for a spare wheel. The whole car's refinement was appalling, with NVH from the now alloy block horrid, and the run flat tyres so dangerous in the wet (and sometimes the dry) the car should have been illegal. These tyres would make the car veer wildly in almost uncontrollable fights under certain camber and road conditions. On country lanes its ability to try and jump in to a hedge violently, made carrying 30mph to much in to a nasty corner on a vintage bike look sensible! It was fast but the combination of runflats and lethargic throttle response meant you couldn't trust it to go, or do what you wanted when you asked it. The only great feature was its distance cruise, which was light years better than the 221 but gave up below 15mph as it couldn't do town work with one radar

After the 335d BWM, I got my W221, an early LWB that came with the standard 235 x 55 x 17" Michelin Primacy 3 tyres. Its a big car, but its ride and handling on the 235's was OK, I then fitted winter tyres and it was light years more unstable, with a lot of wobble from the back and a loss of grip and more noise. But I got used to it and did 3 years like that. I had expected to fit OEM 18" wheels and std tyres when spring came round but never got round to doing it after buying them within the first year of getting the car. I was trying to get it reliable and adding toys all of which took too long.

Then the Winter tyres got worn out and I had the OEM 18" refurbed and fitted stock OEM 255 x 45 x 18" Dunlop tyres. And the combination is just shocking - it handles like a pig, drives like a pig, and is noisy and rough where once it was quiet, composed, safe and much much faster !!!!! I still can't believe how bad it is. The ride as I have said before is like the "17 inch, plus sport button, plus 20% stiffer" and its too much the car just shudders and skips across the roads where once it gripped. The tyres are so wide, it now doesn't turn in with any form of alacrity. Instead of some nimbleness and fun of the 235 17's, it just wants to go straight on a smooth road, whilst being noisy and less comfortable. And in the cold (less than 10 C - I guess 50F) ride comfort and any form of braking is just completely absent.

There are two suspension types

optional ABC better but expensive and needs ideally annual fluid changes and maybe that software tweak https://benzninja.com/special-tunes/
or the std air tragic that is just woeful

I suspect if you have airmatic - bin it and fit an arnott steel spring conversion with combinations of tyre brand and wheels that are less radical than 20" wheels a 2" drop on air tragic and budget tyres


.

 

Having actually read your whole post - I now realise you have done a lot of work to make it a standard car in roadworthy conditioning - yet you still hate it - and it sounds more like you are asking a question on why its like it is ?

the big clue is air tragic suspension and what you are used too - if you are coming from grown up car manufacture's that use real springs to your first air tragic suspended vehicle that's a huge part of the issue you feel - buttons on a dash to fiddle and make it from naff to horrid is a marketing job to impress ignorant and impressionable fools. But steel springs and high quality dampers, have no real revenue stream after sale - so fit overly complex unreliable crap and you can fix both impressing fools, and stealing money for the rest of the cars life rather easily.

however a few basics ideas and one interesting "feature" that may help stability
.

• ride height - the w221 is a wallowey mess of un-composed incompetence - but it will be worse with seized level sensors (they all are, and then snap off with even more fun). If its sitting slightly low but thinks its right, it runs lower pressure and floats more
• Sport doesn't help it just makes an un-composed stiffness of disjointed nastiness, yes there's more wallow and float at the back when using Comfort but overall its less appalling
• tyre load rating - its a heavy car and uses 99 load index tyres if you are running less expect it to be strange
• tyre pressure, german's do 130 mph every day to work, so they run 36 psi min to stop the tyres going pop
• they all leave the factory with incorrect slap dash geometry - the front camber is usually at the very edge of manu spec (and its better moved to the middle) - you can fix with silly slotted bolts or use the original proper bolts and just use the silly washers and shave off the lug on the subframe
• my 221 is generally all over the road - its worse than any car I've had before (by a lot) - it got more vague on the winter tyres (expected) and didn't really get the improvement I expected on the 18" wheels with summer tyres.
• German cars behave far better at real speed as that's what they do where they make them. Both my Omega's only got stable after 120 mph and became sensible at 140 mph, my w221 is the same (I guess its the aero-dynamics).
• However I found one setting on mine that seems to have made is wander much less - I thought it was only ABC that got cross wind compensation but I'm not so sure these days (somehow it messes up the suspension to try and counter sidewinds) - whilst rummaging about in my snap on tools ability to break the 221 I found a "steering angle correction" setting that is user mess-up-able. Looking at it was on 10.9 degrees and I said no it not its 0. Nothing appeared to change in the way the car drove but I subsequently noticed it seemed a lot less unstable on highways. Then I changed the Rear SAM (to resolve a different fault) and after a while I questioned myself if its really wandering less. A few months later the snap on tool got an update, so I had plugged in to see if they had bothered to support any more than the 43 out of 62 available modules (which they haven't !!!). Where upon under the same menu about steering that gives NO indication you are looking at the Rear SAM (it has its own section) I found the steering angle correction is again in a similar place at 11.1 degrees. With the geometry correct, tyres pressure correct, ride height correct and the wheel dead ahead I said its 0 degrees and the car becomes less unstable once again. Its still appalling but it's 50% better

.

 

Thank you for the input. When i bought the car it was fitted with the OEM 20"AMG 10 spoke staggered set, so 8.5F and 9.5R. Offcourse the seller put 4 damaged wheels just prior to deliverance on it, so exchanged them with 4 new ones. You can imagine the costs..and why im reluctand the change them to 17". Im in the aspect now that its quite good qua handling, just looking for owners who improved the handling by upgrading OEM parts. I understand what u mean, and i appriciate it allot, but down to 17 is a no go for the moment. Due to this being a US forum i was under the impression that a few people were here wich also encountered the sluggish handling and replaced/upgraded some suspensionparts. I mean, i see Youtube full of stuf of US people upgrading the most difficult things on a car and hoped a w221 chassis passed though that same avenue a few times. Thanks Botus.

 

I don't think swapping to 17" is sensible - but it does make it drive better

I'm not so sure airmatic tries to help it stay straight - but there was a calibration bit for the steering angle and its definitely more stable when it has the wheel and the numbers matched up correctly. It transforms mine from wandering highway madness, to almost normal - which I guess it would when its not fighting against you

FYI 4 wheel steer is becoming popular on expensive cars, they can both help stability at high speed steering the same way but make it more agile by steering like a skate boards at lower speeds.
Ferrari at last have started development of individual rear steer to give all the agility and safety benefits it would... They have for about 4 years had clever tricks (side slip control) and in the last two perfected it to make it so you grandmother can drift safely. I guess 4 wheel steer with bring more speed and even less need for electronic magic to get round the corner

From here https://en.wikipedia.org/wiki/Merced...n_and_handling This says its the cars with Active Body Control (ABC) crosswind stabilization – uses the sensors of the Electronic Stability Program (ESP) to vary the wheel load distribution via the ABC spring struts, depending on the direction and intensity of the crosswind, in order to reduce the adverse effects of crosswinds. This is standard on the S 600.

The picture below was yesterday from a Snap-On scan, seems a bit random.... I don't have a heated steering wheel, high beam assist or the wobble the steering wheel assist it says I have ????

 

Ok, thanks for the suggestions, but all those were allready multiple times checked. Last week i went driving a W222 and it drove really, really well. A completely different handling. Stiffer steering, mine you could turn like a 60"Caddilac.It was a stock 400D swb with original 19" rims. Much smoother Airmatic It drove so much better that i bougt it. I had so much trouble since of the beginning with the W221 that i made the decission to buy another car.
Driving the W222 it seems that the problems with the W221 were in the back. It was sluggish and the whole car went on the stangest moments its own way. I wasnt in control, so it felt. It lived its own live pulling from left to right and vica versa. Sometimes the front would just pull for a mile to the left, changing it the next mile or so to the right. Or sometimes not. So strange. Eve-re-thing was changed and i visited tens of shops. Nobody could explain it. So now it goes. I had enough of it. But thanks for the input Botus. i appreciated it.

 

WOW!

After all work you did to the 221 you bought a new 222?!? How do you like the looks of it compared to 221?

How long did you have the 221 you tried to fix? My simple question would have been what diameter sway bars does your car have?

I have a 2013 S550 and it is so stable on road it is unreal. It is with the sports package and I can tell you it is very difficult to make this car to lean in fast tight curves. I’m sure it leans some but I cannot feel or see any and I have tried many times. It will fish-tail before I can make it lean for me to feel it. Sway bar stiffness is one important part of this.

Also, the car has accelerometers and there may be a function from readings on those that are used to stiffen the shocks. Did anybody check that the accelerometers work correctly. They may appear fine for the car’s systems and pass the test but may not give correct signal. Like if the signal is “flaky” it could be changing shock stiffness and make the car “wander” on a straight road.

 

Well personally i loved the 221 qua looks. One of the best since the "90. The rear, the front fenders. I had a 350D AMG swb and on every angle it was perfectly balanced. The 222 is like a E-class but bigger, litterly. It has almost no identity on its own execpt its size. But you know what, i didnt care. The AMG was too much an eyecatcher. I mean, i drive the car as a Taxi so the customers werent really that happy with 20" AMG polished wheels as i did. So i made an choise not to buy an 222 AMG. They look a bit better, defenately in lwb, but i wanted a more anonimous car. One who would bled better in the rest of the traffic. Then it becomes more difficult, cause 90% of the 222 is AMG package equiped. After a while i found this one. At first i wasnt that impressed by the 400D 4-matic label (fuelefficiency=taxi) and rather had a 350D. But ride and engine were so good that i made the deccision. Sure it has costs. Many many costs. i think the whole "thing" with the 221 has set me back €20.000 ore more for parts and labour and still it was a dog. I had no more fun in it. It wasnt a car that you would jump in and take it for a fun drive. Its straight out stability is a complete nightmare. And the comfort with its 20" wasnt any close to the 222, wich has 19". Soooo smooth, like hows supposed to be, short said.

I've changed EVERETHING qua dampening and steering of the 221. I had it for 3 years. Steering rack, all 4 shocks, subframe rebuild. Wheelbarings. Name it. And yes also the swaybars. All OEM and original, so no Ebay stuff. The accelometers werent tested, the shops i visitedwere ALL convinced that my inputs werent right. You know what i mean. Its very difficult the make a shop check thing I suggest, if not impossible. I have bin to multiple official "experts" who all diagnosed my problem in 5 minutes. Thats the thing with these S, you hardly cant get around buying a Star yourself! Asking "Them" to check the righthight WITH an inclignometer? Hahaha. And you would like to with that diagnose to see for yourself? IM-POSS-IBLE. So you know then the way ive been with all these visits to "dealers", "experts" and "specialists" . When it becomes difficult, you and your car can take a hike. Were looking for the easy stuff.

I was done with that. I had litterly enough. I drove to the next best MB dealer and if luck dicided he wasnt done with me, a nice and bit dull 222 was there on the look for a new owner.

 

Yes, the looks of the 222 is like the E and C class. From the distance you don’t know which one it is.

MB went to the same as BMW did years earlier making all sedans look the same. Only difference outside is the size. In my opinion very wrong direction with the design and I think BMW is now going away from it a bit.

I think the 221 is the best looking S-class ever. It is very distinctive look and recognized immediately.

But, the looks opinions is just that. Others prefer something else than I do. I believe though that there are a bunch of people who think the same way of the looks of the S-class.

 

Sorry to necropost but wondering if OP is still around. Found this thread searching for something else. After reading, I was left wondering if the OP replaced those bushings in the rear knuckle where the spring control arm attaches. We have discovered more recently that these are really a key component to rear suspension stability over imperfect surfaces.

 

yep, was a great find you made kevm... OP says he even did rear subframe mounts... and I 've had some one say mine needed those - nope that's a lie - but either they call these hidden bushes by that incorrect name or they really have no idea about how the cars work

 

here u go the link you posted originally

https://mercedessource.com/store/w22...eplacement-kit

 

I ordered that kit after he posted that video. Someday I'll do that job as well.

I've been subbed to him for a while. He's a great guy. Had his comments turned off forever but for some reason turned them on for his latest videos. Probably learned about YouTube "engagement" because not only did he turn the comments on, he started asking questions for the audience to respond to in them.

 

I ordered it and replaced the bushings. It made a huge improvement but not quite perfect, but surely a lot better. The bushings that came out were very soft rubber.

Next, I will install K-mac adjustable bushings in the other end of the control arms for getting the camber right that the MB construction does not allow to correct. Got the kit from them but the tool was wrong and had to wait for the correct one. Will get to this job in a couple weeks. Anybody ordering this K-mac kit after placing the order email them a reminder to send the tool with long enough threaded rod.

But, I think a big player in this is the too weak sway bar in the rear (or front). My car is a 2012 model. Before this one I had a 2013 model, which is the same car, but that one behaved way better than this 2012 model does. It did have 20" wheels while this 2012 has 19", but I don't think this makes so much difference?

For trying to help the issue I replaced the rear struts with the Bilsteins. I had no problems with the ones the car had but thought if this could help, but it did not. I did this job before the bushings.

My current car seems to be rocking too easily, like the sway bar is not strong enough. Wonder if there is a difference in the rear (or front) sway bar diameter between 2012 and 2013 models?

 

I have already made the observation that this car needs a bigger rear bar just from a balance standpoint. Understeer is really excessive. But there is no larger bolt-in bar, is there? I tried to poke around EPC and there was only one - the higher end cars all had ABC with no bars....

 

What year is your car? Like I said the 2013 model behaved a lot better so could there be a difference in the bar?

Looking in the EPC, does it allow to look at all parts on all models? Does 221 AMG have the same bar or are these all with ABC?

 

I guess give me a 2013 VIN and I will check. But yes you can uncheck all the boxes that limit the results to ones that are compatible with your car and just list like everything available for that chassis and I still didn't find anything else.
And yes the AMGs all had ABC.

 

stiffer bushes would effectively make the complex shaped rear ARB stronger

its a 221 the back coming round isn't so clever, most drivers can't cope

 

In what ways? I find that hard to believe. They are literally the same car, one just being produced a year later.

 

My 2013 was: WDDNG7DBXDA515826

 

That car had almost no "side jump" in the rear at all. This 2012 feels it wants to sway and side jump on uneven roads and even when I hit some hole or bump on one side. This was very bad before I replaced those bushings, and I expect this to get better yet after I install the K-mac bushings in the other end of the control arm. K-mac has some sort of much stiffer material in the bushing instead of that soft rubber that the original bushing use.

But I think the sway bar really needs to be stiffer in the rear and I have little difficulties to understand why the rear bar is so flimsy compared to the front bar. Huge difference yet they both control the same stiff body of the car.

 

It's probably a bushing issue.

Here is what my research revealed with your VIN (and comparing to my 2007):

Factory rear bar for your 2013: A2213200411. This part is also listed for my 2007 S550.
Front bar for 2013: A2213231765

Other front bars listed:
A2213230965 (the correct one for my 2007 S550)
A2213231965

I don't have the specs on any of them.

No other rear bars listed on either my 2007 or your 2013.

 

Those rubber end caps are only there to hold the grease in.
Inside the bushing is a steel ball that can rotate inside a round steel hole.
I'd be very surprised if the rear swaybar was diffewrent between 2012 and 2013.
Most likely there are still some worn buschings somewhere.

 

the ARBs at either end likely has no bearing on the jumping sideways issue

but silly diameter and silly width tyres likely contributes to a lack of compliance - 235's have enough grip for traction - any wider and its just picking up imperfection on the road and throwing the car around needlessly

 

Has anyone considered the effect of wear in the steering rack or power steering? Changing the fluid might help as it does degrade over time/use.

When you go to town on the suspension, you have to pay very close attention to the minutae of the settings. In the green just won't cut it and it will drive like a dog but there are other considerations.

The S Class is a very capable car on the road even if it's bulk suggests otherwise. I've not had cause to get into the set up on mine, although it's a bit twitchy following a set of front lower arms, but at 129k on a set of Goodyear Eagle F1s, 255/45/18 103XL all round and it still goes exactly where you point it.

Comparing the Omega suspension and handling to the S set up, even a W140, is largely a nonsense as it's got more in common with a W116/126 from the 70's. That said, a well sorted Omega with a few minor bush upgrades and precise geometry will give an E39 M sport a run for it's money on a fast B road, even an ex police estate on standard springs/shocks with 245/40/18s.

* Other factors include things such is condition of the drive train mounts... A pair of failed engine mounts will give you a pretty hefty pendulum effect when changing direction.

If either subframe has been removed, is it in EXACTLY the same position when refitted? A mm out and everything else will be cattywampus. There won't be much wiggle room, but moving the subframe can tweak the lower hub ball joint position fore/aft, left/right. The rear subframe will have less effect but could cause the car to crab if it's off centre or rotated relative to the chassis.

Also tyre choice is significant when it comes to handling, likewise tyre pressures. And if you've changed the wheels as part of the work? Wheel width and offset have a direct impact on the geometry as you turn.