Hello everyone, hope you are all well. I would like to ask something about rear axle steering; the ones have that option, do you have any problems regarding to parallel parking or is it easier to park?

 

Might be one of the first cars where it's actually advantageous to let the car parallel park itself, because it can control the rear wheel steering and effectively kinda crab walk in and out of the parking space as shown in the video below. Can't take advantage of this if you park yourself.

 

That looks actually very good! But may I ask if I somehow cant engage the parking assit, will it cause any difficulties to park? Because once I read a thread on another forum that it makes the parking very difficult without all those things shown on video. I am now strongly considering to order s class and I am still not sure to add rear axle steering or not due to the reason I have just mentioned.

 

Are you certain it only works with Park Assist? I seriously don't think so. I think even when you park/steer yourself the rear wheel steering works. Just because the referenced video only shows park assist doesn't mean it can't be used other times.

On another interesting note, the sound of the "autonomous emergency braking" (as seen at 3:03 mark in video) is extremely loud (louder than the video). Scares the heck out of me every time! First time it happened to me I didn't know what it was and thought I hit another car in the rear. I only realized when I got out of the car to see the extent of damage. I was happy to realize that it was just the braking.
No joking, it is seriously loud! Once a parking attendant also though I hit something.

 

No, they work in all circumstances but what we cant do is direct the rear wheels the way we want.

During the summer I was down in the Village grabbing a pastry for Mrs Crab. I decided to snag a cappuccino at the same time and was sitting outside waiting for it. I had parallel parked right in front of the shop; tight but not too crazy. The car in front of me pulled out while I was waiting and a car pulled into that spot and ended up well in back of his spot, for a second, I thought was going to hit my car. But he stopped and got out with 6 inches or so between us, and it was already tight but not unusually so in back. He had women with him, girlfriend or wife by the way they interacted. She said he needed to move because he was too close but he gave her some meh action, and they went into the shop. I suppose you never think they guy you just jammed is sitting at a table listening to your conversation about screwing him over while he waits for his coffee; but there I was... In any event they brought my coffee and I decided to see what Mercedes could do about getting me out of there. Turns out she had it in her; crab-walked back and forth till I was out.

They were watching and I believe the word to describe the look on their faces would be; priceless.

No matter how good a driver you are you can't do that. I've come to an understanding with the system: If a spot is very tight I let it do its thing. The system is a little slow so I do it myself if the spot is normal or just tight, but not very tight.

@emrebenz The rear steering is a huge help in tight lots, I was surprised for months after purchasing by the turns it can make. You do have to learn to work with it though because there is some weirdness. As an example when you're parallel parking and backing into the spot, you reach the point where you're going to turn your wheels out to get the front in, the rears turn the opposite direction so now your rear end is moving away from the curb at the same time your front end is moving into the curb.Things like that require you to adjust your style a little bit here and there. Some good things happen though that you don't see coming. When you're pulling into a spot front end first, in a tight lot with little room between rows, the scenario you often run into with larger cars is that you made it in, but you're cockeyed and need to back up again and get straight in your spot. The rear steer drives the rear around when you're pulling into spots like that and you often make it in one. In fact, I work with it by going a little deep and then turning more tightly to get the rear to crab over harder. There is more of the same but you get the idea.

Unfortunately the 10 is tied to the exec and the 4 to AMG so your options become limited by that stupidity.

 

Yeah, I got the 10° which are way more important than any 21” wheels! (As previously mentioned, the 10°is limited up to 20” wheels).
Regarding @crabman statement “the 10 is tied to the exec and the 4 to AMG so your options become limited by that stupidity” that only applies in US, most of the rest of world can have best of both worlds.

 

Good point, MB optioning is crap in the US, moreso than most markets.

 

Thank you all for sharing your comments and experiences, I have now quite an impression on rear axle steering and when I order mine, I will order it with 10 degrees steering as it is all fine here in Germany. If I test drive an S class or Maybach S with a rear axle steering, I will definitely share my experience. The part which I was most concerned of was parking the car without parktronic but @crabman made me feel more confident on that. My recent park place is bit narrow so, rear axle steering will probably be very helpful on maneuvers too.

 

Just open the dyno mode (using the service menu)

or

enable the Winter chain mode from the menu. (it limits the rear axle degree)

 

I've had rear steering before, with Porsche it's an oddball number like 2.9, something like that. You can notice that and it's helpful but it doesn't change the way you maneuver the car, it's nothing notewirthy

The 10 degree is a different, and game-changing, animal. Mercedes claims it reduces the turning circle to that of an A class and I don't have trouble believing that. It's not subtle and you don't need to be behind the wheel to notice; several passengers have stated their disbelief at how tight the car can turn in the lots for such a big car.

I don't think you will be disappointed.

 

Yes, I'm sure. As @crabman said, the rear wheel steering does work all the time, but you can't manually control in which direction they turn, so you can't crab out of a parking spot like this manually. The rear wheels steer in the opposite direction at lower speeds.

 

I have the 4.5 degrees and manual parallel parking is much easier. It's also easier to get out the parking as the turn radius is significant than a non rear wheel steering cars. I live here in Europe and even in small tight parking garage, the rear steering saved me quite a few times.

 

So car won’t “automatically” crab when steering ‘manually’?

 

That's correct. If you manually point the front wheels away from the curb in the direction you gonna move, then the rear wheels will be pointed towards the curb and cause the rear of the car to move closer to the curb instead of away from the curb.

Below a certain speed the rear wheels do the opposite of what the front wheels do. So if you point the front wheels to the left, the rear wheels will point to the right. This has the effect of making the car smaller and reduce the turning radius. Helps you when parking perpendicular as explained above, because it brings the rear around, but can be counterproductive when parallel parking. At higher speeds the rear wheels mirror the front wheels, which has the effect of stretching the wheelbase and increase stability on the highway etc. when changing lanes.

 

Thanks for your detailed explanation.
On a side note: my understanding is that in order for car to automatically steer OUT of a parallel parking spot using Park Assist, you must of PARKED IT automatically. If this is not true (which I hope is not), is there a way to automatically exit parking spot? For example, one might park manually into a wide open spot, but when return to car, its jammed between other cars.

 

I'm guessing you don't have much need to parallel park Sonic? In any event, no, it doesn't put up the toast to get you out of a spot unless it put itself into the spot. Not really sure why that limit is there, the cars front or back often move while you're parked and it will still offer to pull you out regardless of how they've moved around. I don't see any reason why it can't be on offer at any time for those situations. But, Mercedes... *shoulder shrug*

The steering isn't counterproductive when parallel parking Swiss, but you have to do things a little differently. Imagine you've just parallel parked up to the point where you're in there, and you look at how you're sitting for a final adjustment. Say the front is out 8 inches and the rear 6; not quite right so usually you would back up a little more with the wheels turned out to get the front in further and then pull ahead again after straightening out the wheels. Do that with rear steer and while the front is going in the rear will be going out, so your front is in, but now your rear has gone out. Instead, you do something like a mini parallel inside the spot where you turn your fronts toward the curb which drives the rears in further and then turn the fronts back out to get the the front in. The rear will be too close for comfort but when you pull ahead again to get centered in the spot you turn the front in and it will go toward the curb and the rear will go out but now with the whole thing closer to the curb. This kind of thing isn't a major factor but it does play out so as you can notice in the car when you've got 10 degree. As I type this it all sounds more complicated than it is; you adjust quickly.

What I found was that you really don't run into once you get used to working with it in the first place. What I did at first was pull in the way I always do and the rears would be out too far because they countersteered out while I was getting the front in. You learn to back in far enough you haven't hit the curb, but it would be too far for a normal car where the rear would hit the curb while you were pulling the front in because you went too deep. With this car the rear counters back out somewhat so it ends up working out. Takes some getting used to, again it's not a big thing, it's just more of an adjustment than you usually make when backing one car in versus another.

A few other tidbits: I've tried to see if it would crab itself into a spot but as near as I can tell it isn't a possibility; it doesn't 'see' those spots and offer them up as a potential parking spot. If the road is heavily crowned but the curb is flat it will park itself out farther so that the passenger door can't possibly hit the curb when it's opened; often it's too far out and it seems to be very conservative on its estimation of what may be a potential door strike.

 

If you have 10 degree rear wheel steering, the car uses cameras, parking sensors, and radar to determine how many degrees of rear steering to give you at any given time. If you're next to a person, wall, curb or other cars, the car limits the rear steering to 4.5 degrees. This is so you don't accidentally swing the back end of the car into something, an issue you'd never run into with no rear wheel steering or only a few degrees of rear wheel steering.

If you want the vehicle to crab walk out of a parallel parking spot, it has to be like a spot shown in the demo video above, with no curbs on either side of the car, otherwise it won't crab walk fully, just partially. It also won't crank the rear wheels opposite of the front upon exiting the space if there is a curb. If you drive manually out, the rear wheels will steer more than if it was doing it automatically, but doesn't give you all 10 degrees until you're clear of the curb/other objects.

You can use the "Info" -> "Vehicle" menu to see how many degrees your rear wheels are steering at any given time. If you pay attention to this in close quarters, you'll see when it decides to limit the max degrees of rear steer.

 

You are very verbosely exactly describing what I meant by counterproductive, so you are making my point. I'm not saying it's difficult or that you can't get used to it, but as you said the rear moves in or out when you don't necessarily expect it, at least when coming from cars without rear wheel steering. There's at least somewhat of a learning curve as you describe yourself. Considering how some people struggle with parallel parking in the first place, this is an added complication.

 

My apologies, less verbose: Rear wheel steering is not counterproductive. Turn the wheels the wrong way or at the wrong time without rear steer and it doesn't work. Do it right and it does. Same-same with rear wheel, do it right and it works fine, do it wrong and it doesn't. Almost anything can be made counterproductive if you don't do it right. Succinct enough?

 

Are you disagreeing with my use of the word counterproductive or are you disagreeing with yourself? The fact that you needed 4 paragraphs to explain how to parallel park with it kinda proves my point that there's a level of extra complication to it. At a minimum it's an extra variable to factor in, and particularly a variable you have no direct control over, because the electronics decide how much to turn the rear wheels and in which direction. You can only control it indirectly. Do you prefer if I called it counterintuitive?

 

The hardest part of the CDL State Road Test was parallel parking a :TRACTOR TRAILER: in a simulated tight space mapped out with many Orange Cones. Get it right and you're a Hero. Hit any Cone and you're a Zero...lol