A dear friend of ours, who was an American citizen, made the mistake of driving in the left lane her first time in Germany. Until the police “talked” to her. I understand it was a brutal chewing out. My wife and I have both been fortunate to drive on the autobahn. More than 120 in an old ML320. Smooth as glass. And as Swiss pointed out, no big deal.

Well said. Especially this part. The USA has some horrific drivers, and speed limit enforcement has been implemented purely as a revenue stream for local governments. I've been ticketed for going 83 on a 3 lane wide straight highway after 11 o'clock with not another soul on the road. There is absolutely no reason that isn't OK. I'm still annoyed by it tbh. On that particular road you can cruise at 120 with 0 issues so long as traffic permits. For years I've dreamed of improved driver education and subsequently, more reasonable speed restrictions. Sadly, I don't think it will ever happen in this country. Even if we solved the issue on the human side of things (good luck with that), the infrastructure is not up to snuff to support those speeds safely in most areas. It really is a shame...this country is SO large and has such a massive network of highways....being able to travel more quickly without the fear of molestation along the way would be great....a guy can dream I guess.

Lousy roads. Lousy drivers. Lousy habits. Too many electronic distractions. Vehicles not safe for the road.

I was driving and towing customer’s cars on the streets of Philadelphia at age 12! I was helping my father push or tow their cars to his auto shop in the snow when they wouldn’t start or just died for some reason. Sometimes at night. I’m 72 now. I’ve driven most types of vehicles in most every weather conditions on every type of road. And through all that? Drivers scare me the most.

Yeah, German cops are not shy when it comes to chewing out people. I saw this documentary once. Don't remember specifically what it was about, but they were following cops and interviewing them. There was this one scene with a fatal accident on the Autobahn and all the drivers rubbernecking as they were passing, some even taking out their smartphones to take pictures. Yes, happens in Germany, too. But the cops were pulling them over, especially the ones that were taking out their smartphones and asking them if they wanted to see the dead body. No joke, they totally confronted them with their stupid behavior. The cop afterwards said confronting drivers with their own behavior is the best way to get them to change their behavior. Those that got pulled over were all embarrassed and didn't know what to say. I wish this stuff would happen more over here. I bet your friend kept driving on the right after she got her chewing out.

On a three lane Autobahn, trucks must not use the left lane. Therefore the risk, that a truck changes into that left lane, is very, very, very low. However, as trucks in Europe are limited to 55mph, one has to monitor cars that approach those trucks form behind closely, as it is likely that they are going to change in the left lane.

High speed accidents are extremely rare. Most accidents on the autobahn happen due to not recognizing traffic jams ahead...

Maybe an american driver feels more comfortable on an empty Autobahn:


The point is: The C63S with stock 19" and Michelin PSS runs smooth and stable as hell at 180 mph. Except - the fuel capacity is way to low. At a steady 112 mph cruise, that car takes (in a station wagon), all you get is 13.5 mpg...

You are right Superswiss, I have never been on the Autobaun so I cannot argue your point. I am in total agreement with your assessment of lenient laws about obtaining a drivers license in the United States. You mentioned people being able to obtain a drivers license by taking a driving test around the block. I have one better! I'm a physician (Podiatrist) and my first office was in a shopping center. A few years into my lease, the state of Florida opened a drivers license bureau in our center. The driving course consisted of just driving in the parking lot, not even on the neighborhood streets. I'm assuming for safety reasons. I guess the state figured it wouldn't be as dangerous. That was until my wife and I were coming back from lunch one day only to see a care flipped completely on its side. A person taking their driving test, hit the gas instead of the brakes and hit a curb causing their car to flip. One of the big problems in South Florida are some of the elderly people still driving. This is partially due to a lack of enough public transportation. I have literally convinced several patients to give up their drivers license. One very scary and sad story was a couple came in for their appointment. It was obvious the husband, who was the driver, had bad vision and the start of dementia should not be driving. I approaced his wife to discuss the fact that her husband should not be driving and it is my responsibility to get him off the road. Her responce was insane. She said she helps him while he drives. I asked how do you help? Her answer, because he doesn't see well, I tell him if the traffic light is red or green. Needless to say, that was the last day he drove. I ended up calling their children, and would have called the state if they didn't obey.

Has anyone driven in New Orleans, Louisiana? Here driver's licenses are often ignored, cars don't have valid license plates yet alone registration, and chances are that the car who hits you has no insurance and it's a good chance it's stolen, sometimes driven by a 13 yr old. Traffic laws are unenforced and the city interstate drivers speed far past posted limits with a group (gang) of drivers cutting trough traffic a couple feet from your rear. It's the Wild West and there's no sheriff.

Yeah, I'm in Biloxi and driving in New Orleans is like being on a race track with no rules. Along with the extremely bad roads over there I make sure and drive my SUV every time I go that way.

Yeah, I'm in Biloxi and driving in New Orleans is like being on a race track with no rules. Along with the extremely bad roads over there I make sure and drive my SUV every time I go that way.

Yeah I actually had that exactly same experience with mine (coupe) when braking real hard at those speeds with suspension in Comfort. It's almost like the car would float from side to side.

I got up to 165 on the 15 to vegas a few months ago in comfort mode
felt smooth as can be

The issue you are experiencing is that the rear of the car is starting to "take off". This is super not safe. This is especially why one shouldn't mess with adding/removing factory rear spoilers. For ex, if that little spolier on a Boxster/Cayman doesn't come up around 75mph, the back end of that car would literally lift off the ground. So when you brake at that high speed, you are helping the back end "lift up" off the ground and the traction control fights to stabilize the car (the shimmy/side to side feeling that you get). If one were stupid enough to have turned off traction control at those speeds, they would have been strong Darwin award winners. This is also why the McLarens have that awesome rear spoiler that "tilts" to add rear downforce during braking. It keeps the rears planted.

On a separate note, a 911 C4S gets "light" around 120 mph on throttle. But then "hunkers down" around 130 mph and feels incredibly solid all the way to 170mph. It's interesting how aerodynamics work at different speeds.

I have a ‘19 c43 governed at 130. It is still pulling hard at 130. Very stable. It’s awd but I would assume it would run to 150 no problem stock.

harsh guys, no question is dumb!
obviously he wanted to know .. as an enthusiast and onwer

this is why i dont post on here anymore ! B** A** bully's

hey bro !
Track day as a rookie and 3 laps
Mich 4s - I hit 109 straight away and felt planted

You need to track the car and find out ! we have no way to tell you how your car reacts.
to many factors, weather , Road conditions , etc , car setup , style of driving

I have a 2020 c63s coupe. I have the exact same issue as you. Braking at high speed the rear becomes very unstable. I'm coming from a f80 m3 comp pack and a alfa qv. Both those cars felt alot more stable at high speed. The coupe is not easy to drive fast.

thats strange as I have a coupe & don’t have this problem braking at 189mph. Going at this speed you will need a good highway with no pot holes or any big imperfections. Have you check your alignment and tire pressure? I find that whenever my coupe is out of alignment my front end and back end will get light & the whole car just felt unstable

Just curious, what mode are you in when driving at high speed? I can't relate to this at all. The coupe is rock solid at high speeds in the proper mode. Not Comfort obviously, but S+ or Race and the thing obliterates fast roads. Race is my preferred mode when bombing down a canyon road for example. Just came back from a 200+ mile canyon run today. Also put ESP in Sport, so AMG DYNAMICS is in Master mode when you select Race, otherwise it stays in Pro. Admittedly, I have the aero package on mine, so the rear is more planted than w/o it, and I haven't driven a coupe without the aero package at those speeds.

Any mods on yours that pooped your suspension geometry such as spacers, aftermarket wheels, non-factory size tires, lower suspension etc.? Also, make sure your alignment is good. Just had mine aligned last week for the third time, and I can tell that it drives better again. Not that it drove bad before, but the front end today was more communicative. My toe was slightly out again. I do have to say I was not a fan of the OEM PSS tires at all. Much better with the PS4S and make sure you use proper tire pressure. If too high it will also start to swim around. 33 psi front and 32 psi rear if you are by yourself.

Let's get to the bottom of this.....

I also experience this bizarre WOBBLE when braking hard at high speed.
Mine's a pfl. But it seems fl owners are feeling this too.

The best way to explain this is the rear is almost swaying from side to side as you momentarily brake hard at over 100mph.

Accelerate very hard at highway speed and hit around 100mph/160km/h........

If you suddenly hit the anchors after accelerating at this speed, this car will sort of lift up in the rear and wobble around for a brief moment until it regains itself.......

For me my car is coupe stage 1 tune 600hp
Comfort mode
Full tank gas
Myself and 1 passenger
OEM red brakes, pads and rotors

I'm thinking brake bias is playing a role combined with comfort mode suspension settings being spongy?

Are you guys experiencing this only with suspension in comfort?

^ I suspect you guys are feeling the e-diff do its job. It will continuously distribute torque between the rear wheels under hard acceleration and under hard braking to keep the car stable and provide maximum traction. What you are feeling is a momentarily locking differential which makes the car wanting to go in a straight line. The diff needs to be open for the car to rotate, so there's a balance the diff has to find between partially locking to send the torque to the desired wheel and partially open to let the car turn and for braking.

There's also no fixed brake bias. This car has EBD (Electronic brakeforce distribution). It dynamically sends brakeforce to the wheels that can slow down the car based on individual wheel grip. This can cause the car to move around if not all wheels have equal traction, but ESP and ABS will compensate.

However, aside from that, I wouldn't do this with the suspension in Comfort. Comfort mode can get floaty at high speed and quick load transfers at least in the FL. It's tuned for a more subtle ride not for handling. I keep it at least in Sport on the highway to handle quick lane changes etc., unless I'm just relaxing and cruising along.

BTW, somewhat informative are the moose and slalom tests that km77 did with the FL C63S as well as the M4. If you wanna see the rear trying to overtake the front, watch the M4 video. Those of you who haven't had a chance to attend the AMG Driving Academy, I'd highly recommend to do so. The drifting in the paddock area thought me to trust this car and learn where the limits are.

Did a 40 roll with a gt3 on the 405 freeway. Went to 155 and felt stable and planted.

Last October, before I mounted my winter tires, I did 67 miles with an average of 158 mph (as shown in my driver information center) in my 2016 C63S station wagon at night. That car is very, very stable at high speeds.

JMG you're a very experienced owner and I've read a lot of your posts on germany motor-talk forums........ have you heard of any c63s coupe owners in germany who feel this wobble sensation under hard braking at high speed??

I was on my bike on the Autobahn a few years back.....just about flat out at around 175mph....then I became aware of headlights flashing behind me so I quickly moved right.....to be over taken by a Ruff Tuned Porsche 911 Turbo at probably close to 200mph....and at the wheel was this old girl....she was 80 if she was a day!!.....but yes Germany (and to be honest most Western European counties) have a higher standard of driving and a stricter test and licensing system that in other places I've been in the World.

Would you recommend these tyre pressures on a C63S with 19/20s for everyday fast driving for MPS4S also, or just for autobahn speeds?