oriffaz

I bought a 2007 C280 4matic in February 09. It has not really snowed to make the roads bad since this weekend and I have been waiting to try it out. Yesterday with 16" of snow on the driveway (Geauga county Ohio) I drove through it like a commercial. Today, (Jan 4) I had to drive from Cleveland to Cincinnati and back in a snow storm both ways. The car seemed to handle great on the way there. On the way back, the rear end felt like it was fish tailing (sometimes like a boat rocking). Under bridges, the whole car seemed to slide diagonally.

I slowed down to 40-50 in the right lane and was being passed by semi-trucks and cars that were much older and rear wheel drive. Should I be passed by Buicks, Saturns and Pontiacs (Oh My)?

How do I know if the 4matic working correctly?
jim

e1000

BTW, almost all buicks saturns and pontiacs are FWD.

acr2001

Was your ESP light coming on like it should when you were sliding?
If ESP is working correctly chances are your 4matic system is working fine...

Either your tires suck (summer tires? balding all seasons?) or the roads were icing over and you were driving too aggressively. 4matic (or any 4wd system) isn't going to stop you from sliding sideways. ESP should kick in though and prevent the slide as much as is physically possible.

FraKctured

40-50MPH in a bad snow storm is probably faster than they should have been going. That doesn't mean that everyone who is driving over the limit for conditions gets in an accident, however, some who are will careen off the road and wonder why. I've been in many bad weather/road conditions when I was passed by cars and SUVs in bad weather, only to see some of them in the ditch 10 miles ahead.

ESP lights up when you are going too fast for road conditions, so I slow down immediately. Yes, with good snow tires, you should be able to go faster than you could with all-seasons. If ESP is not lighting up (triangle with exclamation mark in it), you're driving within the car's ability to maneuver properly under current road conditions.

The issue (from the driver's perspective) with 4Matic and ESP is that the result of them working is quite unremarkable and somewhat boring--you're on the road in one piece while some idiot in a Pontiac goes sailing past you. What you don't see is when the Grand Am slides into a mailbox. When that happens, you're home sipping a Tanqueray 'n tonic, as it should be.

Dingleberry

this is so incorrect and skewed that it's actually quite funny. you are completely wrong about ESP. you can google how ESP works for yourself - your last sentence is not only wrong, but also dangerous advice. using ESP to determine if you're driving correctly is a recipe for disaster. just think about what you said for a second...i can be cruising at 50mph in snow without the ESP lighting up... if i have to make a sharp turn it's ALREADY TOO LATE, ESP lights up while Igo careening off the road

acr2001

ESP lighting up has very little to do with how fast you are moving. Many factors including speed are taken into account.

ESP is only going to light up if you are:
1. SPINNING WHEEL(S)
2. SLIPPING (sideways, rear sliding out, front sliding out, etc)

If you are slipping because you are on the brakes ESP is not going to engage because that is where ABS comes in. Little known fact though - if you are slipping because of engine braking (down shift) our cars do have a system built into ESP (I cant remember the name) that automatically opens the throttle a bit to prevent loss of control.

Driving too fast could cause ESP to engage if, for example, you are driving on a curved road with ice and the car starts to slide due to the forces from the curve breaking the friction point of your tires.

acr2001

This I don't agree with...

The result is very noticable and not at all "boring". I drive my W203 MUCH harder in snow and ice than I would any other car because when I do begin to lose control it is very noticable - ESP engages and you feel the car straighten out. ESP is in fact so noticable that you can (don't try this and sue me) go around a snow covered turn with the gas pedal to the floor and the car will only put down as much power as possible while still retaining control. Now if you hit said snow covered turn already doing 50 MPH... simple physics will win out over ESP all the time and you'll probably hit a pole.

Our E class isn't a 4matic and driving it in the snow is painful. The ESP system in that car (being different in a non 4matic) is not as helpful when you start to slide out.

Of course on some roads nothing is going to work:
http://www.youtube.com/watch?v=8hemAjudq4g

Notice the M class about 30 seconds in? Why isn't his ABS kicking in? Anyone?

More? http://www.youtube.com/watch?v=KyfjZlOSq2A&NR=1

oriffaz

It was straight road and the ESP light was not coming on. Under bridges, it was a quick slide which was corrected, but felt like I was going to spin out.
Other times felt like the rear end was doing small fish tails

Dingleberry

get your alignment checked

PC Valkyrie

The 4Matic system in the W203 C-class is a very simple one, from a mechanical point of view. There are no differential locks anywhere. Rather, there are 3 open differentials (centre, front, rear). Torque is distributed 40% front and 60% rear all the time as a default. If any wheel loses traction (or starts to spin excessively), it is braked and the torque is thus transferred to the other wheel through the open differential, which presumeably has more traction. The 4ETS (electronically controlled traction system) which controls all this braking of individual front and rear wheels has nothing to do with correcting oversteer or understeer situations.

Rather, it is the stability control component of ESP which corrects for understeer/oversteer. ESP is an umbrella term which includes ASR (acceleration skid control....ie traction control to enhance traction of the drive wheels) and stability control to correct understeer/oversteer.

It would be very difficult for modern Mercedes cars to "spin out" when ESP is fully on and when you are driving straight. If you are aggressive with the throttle in traction limited conditions (like on snow) and the rear of the car starts to slide out, ESP will quickly activate to brake the appropriate wheel(s) and cut engine power to bring the rear back in line. This is the same whether the car is RWD or AWD.

acr2001

Sounds to me like it's working fine. If you are a little aggressive or if the roads are extremely slippery, you are going to feel that bit of control loss before ESP kicks in. Next time it snows, take your car to a big open EMPTY lot and get yourself better acquainted with how the system works.

This article gives a pretty good explanation:
http://www.autoevolution.com/news/me...ned-14334.html
Although the article is about the newer generation 4matic system, all of the info in that article is still very similar. The 40:60 power split was changed to 45:55 on the newer system.

oriffaz

Thanks to all for your insight. On the freeway on the way home today with wet roads, the car slid over expansion joints and still felt as if the back was swaying. As it is still under warranty, I have a service appointment next week. I will update . . .

acr2001

Your tires must be shot...

BF_JC230

Ditto...

http://www.insideline.com/features/t...vs-summer.html

We just put on a big trip to Cleveland, Detroit, Akron and back with NO problems...Driving tonight...No problems - Great snow tires.

Around here...I would assume that 99% of all winter accidents are "PE" or Pilot Error...

I would get some dedicated snow shoes on dedicated snow rims...and put them on when it is a steady 40 degrees.
Jake

FraKctured

I'm completely right about ESP. ESP won't tell you if you're "driving correctly" but it will tell you when your driving requires corrective action by the car. You're using extremes to try and undercut a perfectly reasonable reading of the data being delivered to the driver by ESP.
To use your example:
If you're going 50MPH on snowy/icy roads and you make a sharp turn due to a deer jumping out, or some other emergency, then you've changed the context so drastically, that my comments no longer apply. ESP may help, but the circumstance has dictated a change of context that is likely to result in a loss of control. If you're driving at 50MPH and nothing extraordinary happens, then you're probably fine. However, if you're on snowy/icy roads and you're driving 50MPH, you're making a bad decision to begin with, and ESP won't save you from yourself.

I'll say it again: If you're driving within the car's ability to manage the road conditions, ESP does not light up. If you exceed that, the car immediately begins correcting for you. This is a sign that you should alter your driving accordingly [I believe that MB even says so much in the owner's manuals somewhere?] Yes, there are times when the current conditions change in such an extreme matter that neither ESP nor driver reflexes can save you from losing control.

Why is the ESP light a triangle with an exclamation point in it? The triangle signifies "caution" and the exclamation point amplifies that.

What is it that ESP is telling the driver then? Nothing? "You're driving just fine--keep up the good work." What is the driver supposed to do when ESP lights up? Speed up? Slam on the brakes? Change the oil in 1000 miles?

Dingleberry

it's pretty obvious what needs to be done when ESP lights up

1) close eyes
2) scream
3) slam on brakes

optional: also take hands off steering wheel to cover eyes

FraKctured

I didn't say it wasn't noticeable, I said it was unremarkable and "somewhat boring" in that you keep going where you want to go, as you expect. You definitely notice something is happening. When you lose control, it's definitely not boring--it's very scary/exciting, and if you don't crash, it's quite a rush. I had that experience many times with my RWD C class, and I don't miss it at all. Compared to that, when my 4Matic ESP kicks in, it's not terribly exciting, but I'm happy with that!

Exactly right.

Agreed--the difference between my RWD and 4Matic C Class cars is night and day.

FraKctured

I see how you got your name.

Dingleberry

well since you want to be a smartass, i'll dissect your previous invalid post from a different angle

ESP lights up because it's a system designed to provide maximum traction, therefore it's counter intuitive to continue sending power to a slipping wheel. THIS DOES NOT MEAN THAT YOU ARE GOING TOO FAST. obviously someone that cannot control their car well and does not understand the fundamental operation of the system will just simply panic and slow down...

aaaand there's the proof that you cant drive...

once again, if the ESP light is not coming on, THIS DOES NOT INDICATE ANYTHING. IT DOES NOT INDICATE THAT YOU'RE DRIVING WITHIN THE CAR'S ABILITY TO MANEUVER PROPERLY UNDER CURRENT ROAD CONDITIONS. it simply means that at that time, all four wheels have sufficient grip. use your brain for a second, these cars dont have mechanical differentials, ITS NOT A BIG DEAL IF ONE WHEEL SLIPS, that's what ESP is for, to compensate for the lack of mechanical power transfer - ESP lighting up does NOT mean that you are doing anything wrong - that's absurd

bdgdl08

I am so glad that I live in Florida!!! Last night, though, Jacksonville and even Gainesville got snow!!!

oriffaz

I sucked it up and put on a set of General Ultimax HPs. Of course it has not snowed enough to see if they were the problem.
I still have my appointment on Wed.

FraKctured

I see how you got your name. Again.

Dingleberry

FraKctured

I feel like I'm beating a dead horse here, but consider the "bad weather" conditions of the original post to start with, but even so:

If you are driving 50MPH on dry roads and hit a patch of black ice, you're going to slip/slide (if it's a long enough patch, you'll be in trouble). If you're driving at 10MPH you probably won't slide at all. You're sliding because you've lost traction. You've lost traction because you're traveling too quickly for the icy conditions.

If you're at a stop and you floor your C63AMG, you're going to spin your tires a bit because your wheels are moving faster than they can maintain their "friction point." If you don't floor it, they won't spin because you're driving at a speed that allows them to maintain contact with the road.


The car starting to slide due to "forces from the curve breaking the friction point of your tires" could happen on completely dry roads as well as icy roads. If you are going too fast around a tight bend on dry roads you'll slide and ESP will correct. If you're driving at a speed that maintains the "friction point of your tires" then you won't slide and ESP won't kick in. Speed determines your tire's "friction point."

ESP has EVERYTHING to do with how fast you're traveling. If you drive at 3MPH, it would probably NEVER light up, even in very bad conditions. To phrase another way:

Is there a circumstance in which ESP starts correcting that could be avoided by driving at a faster speed? (i.e. ESP lights up at 50MPH, but if I had been going 60MPH, it would not have engaged.)
Is there an instance where you should immediately speed up when you see the ESP light come on?

Dingleberry

you have no idea what you're talking about. stop spreading wrong information. you need to take a physics class instead of spouting off at the mouth.