DSC vs Rain

Simple answer, pay attention to the road conditions and do not drive in standing water.

If you want to drive in standing water get a boat or snowmobile. The boat takes far less skill to drive on water than the snowmobile!!

Oh and driving through standing water is very analogous to driving a snowmobile on water. Keep it straight and fast you may live to speak about it, one wrong move and the ride ends very quickly!

I commend all the real replies; I applaud all the assholes.

Yes I know what hydroplaning is and have been in situations before. Yes I did slow down once the heavy rain started. You have to realize that I've never owned an E46 or let alone a BMW before. I had no prior knowledge of DSC aside from it being short for Dynamic Stability Control. I realized the car was always jerking and trying to maintain a straight path no matter what, jerking left and right especially at the most unpredictable times. Yes I was watching the other drivers and they weren't swerving or having a tough time controlling their vehicles in the rain. So I thought of the one thing that I had that could have been causing the unpredictable jerking, which was DSC. I simply turned it off, curiosity. I should've checked the thread life.

Originally Posted by E46Cherry

I commend all the real replies; I applaud all the assholes.

Yes I know what hydroplaning is and have been in situations before. Yes I did slow down once the heavy rain started. You have to realize that I've never owned an E46 or let alone a BMW before. I had no prior knowledge of DSC aside from it being short for Dynamic Stability Control. I realized the car was always jerking and trying to maintain a straight path no matter what, jerking left and right especially at the most unpredictable times. Yes I was watching the other drivers and they weren't swerving or having a tough time controlling their vehicles in the rain. So I thought of the one thing that I had that could have been causing the unpredictable jerking, which was DSC. I simply turned it off, curiosity. I should've checked the thread life.

You probably need new bushings all around. I would replace Front Control arms, front control arm bushings, rear trailing arm bushings, and front tie rods. Also replace your steering guibo. If you do this, your car will drive like new. My car used to swerve all over the place too, though not enough to turn on DSC.

Originally Posted by WDE46

You probably need new bushings all around. I would replace Front Control arms, front control arm bushings, rear trailing arm bushings, and front tie rods. Also replace your steering guibo. If you do this, your car will drive like new. My car used to swerve all over the place too, though not enough to turn on DSC.

But this was only in really heavy rain. Light rain didn't even cause any swerving or jerking. It handles well on dry roads too.

Originally Posted by E46Cherry

But this was only in really heavy rain. Light rain didn't even cause any swerving or jerking. It handles well on dry roads too.

That's very strange. Maybe a wheel speed sensor is getting wet in the rain and giving strange readings. You don't have any codes? A yaw rate sensor would do wierd things too as well as steering angle sensor. These all throw error codes though.

Only error code is something about, engine coolant temperature; plausibility. But again it could very well be my tires and the vehicle thinking I'm constantly swerving so it compensates for it when it really is due to hydroplaning.

Well that code is a whole different thing. You probably need a new temperature sensor. You should fix that, because if you have a bad sensor and your car thinks it's temperature is good, you'll warp the head if you overheat.

Anyway, how deep are your treads?

Originally Posted by E46Cherry

Idk if it makes matters worse but they are also run flats.

M3 does not come with run flats. That's why we have the emergency repair kit in the boot. Why do you have run flats. Check your tires for tread life, air, and uneven wear. This should be done regularly.

Originally Posted by fiveightandten

You're in control of the car until you're not. It's as simple as that. [...]
The car can be unpredictable in the rain. It's not like driving hard on dry pavement.

^ This. Like others who have responded, I autocrossed for years, even participated in an advanced school that ended up being held in a downpour. Here's the thing: even if you know what to do to correct, it takes more skill and, typically, a lot more space to do it on a wet surface than a dry one. I am pretty familiar with my skill level and the capabilities of my vehicles. I try awfully hard not to come close to even approaching those limits on the street.

As avincent said:

Originally Posted by avincent52

You were probably one twitch of the steering wheel, or one unpredictable Chicagoland driver, away from a horrendous accident that not only writes your car off, but probably puts you and a few other people in the hospital.

Is there a common theme from these people who know what they're talking about?

Originally Posted by peytonracer4

If you're activating the dsc in rain you're doing something wrong.

Originally Posted by avincent52

The goal is to drive so that you *don't* make the DSC go on.

Originally Posted by WDE46

if you were causing the DSC to activate in the rain, then you are probably driving way too fast.

Originally Posted by fiveightandten

DSC works impeccably in the rain.

Originally Posted by jfoj

You are driving in water that has collected on the road. ... Once the water that has collected on the road is probably about 1/3 to 1/2 the depth of your tread, you are going to hydroplane and then start to PLOW water. It really does not matter how new your tires are or how deep the tire tread is.

Bottom line: if you hydroplane, you're going too fast (relardless of road conditions).
If DSC engages in straight line, steady-state driving on wet roads, you are hydroplaning.

It doesn't matter whether you're doing 120, 80, or 40 mph. And it doesn't matter whether your car has brand new, super special "just for rain" tires or they are 10 years old and just barely at the DOT minimum.

BTW, you mentioned that this seems to happen only in heavy rain. Well, more water collects on the road during a downpour than in a sprinkle. Other things being equal, the wider tires that can provide so much lateral grip on dry surfaces (such as are typically mounted on a M3) tend to hydroplane sooner than narrower ones typically found on other cars.

not very deep from the looks of it. Compared it to our other cars, maybe half less than the other ones

Originally Posted by choxor

M3 does not come with run flats. That's why we have the emergency repair kit in the boot. Why do you have run flats.

Previous owner had the run flats.

Originally Posted by E46Cherry

Previous owner had the run flats.

Get new tires.

Originally Posted by sunsetcoast

^ This. Like others who have responded, I autocrossed for years, even participated in an advanced school that ended up being held in a downpour. Here's the thing: even if you know what to do to correct, it takes more skill and, typically, a lot more space to do it on a wet surface than a dry one. I am pretty familiar with my skill level and the capabilities of my vehicles. I try awfully hard not to come close to even approaching those limits on the street.

As avincent said:

Is there a common theme from these people who know what they're talking about?









Bottom line: if you hydroplane, you're going too fast (relardless of road conditions).
If DSC engages in straight line, steady-state driving on wet roads, you are hydroplaning.

It doesn't matter whether you're doing 120, 80, or 40 mph. And it doesn't matter whether your car has brand new, super special "just for rain" tires or they are 10 years old and just barely at the DOT minimum.

BTW, you mentioned that this seems to happen only in heavy rain. Well, more water collects on the road during a downpour than in a sprinkle. Other things being equal, the wider tires that can provide so much lateral grip on dry surfaces (such as are typically mounted on a M3) tend to hydroplane sooner than narrower ones typically found on other cars.

Got it. Like I said, I'm aware of hydroplaning. I was just unsure of the heavy jerking left and right, attempting to maintain a straight path at all times. I thought it was caused by the DSC alone, when in fact it was due to me hydroplaning BECAUSE of my tires AND the dsc attempting to compensate against it.

Jerking is the feedback you feel as tires regain road grip left and right,,,me thinks

Originally Posted by Alex323Ci

what's DCS?
Dummy Control System?
Dude Can't Swerve?
Drive Car Safely?
Don't Cause Spin-outs?

seriously. i can't believe someone would post such a thread. "haaay guyz. why does my bimmer swerve at 90mph in the rain with DSC off and poor tires?"

Originally Posted by Cobra

seriously. i can't believe someone would post such a thread. "haaay guyz. why does my bimmer swerve at 90mph in the rain with DSC off and poor tires?"

Nice try. Did you even read? That was a reply towards a post regarding Porsche's not having DSC, and a guy mistaking DSC for DCS (acronym spelling). And I said I was driving 50 mph at most in the heavy rain. I think you did a great job making yourself look like an idiot.

Edit: and I mentioned not checking tire threads prior to driving. Again, if you have nothing intelligent to say, I suggest not making yourself sound like a moron.

Originally Posted by fiveightandten

DSC works impeccably in the rain. It does exactly what its supposed to do. Yes, it's intrusive. But it will correct the car before it gets into trouble. You have to be trying quite hard to do something stupid enough to crash the car in the rain while the DSC is on. Believe me, i've tried plenty of times when I was getting a feel for how the system intrudes. If you drive sensibly, the system will keep you safe.

Driving 90 MPH in the rain is not sensible. I mean this in the nicest way possible...you don't sound like you can control the car well enough to bring it back from an unexpected loss of traction in the wet. Keep the system on. I've been autocrossing for a number of years. I've raced in the rain and i'm quite familiar with driving the car past the limits of adhesion in the wet. I keep the DSC on when i'm driving on the street in the rain. There's no reason not to.

Be safe.

yup! electronic stability control or as BMW calls it, "DSC" is a beautiful system and will correct any control situations before your brain can even register that it happened.

Also I want to make an important note:

A lot of people seem to think that DSC changes the driving characteristics of the car in real time as they toggle it off and on: nothing could show one's ignorance or misunderstanding of the system any more than this. That's not how DSC works. DSC is only an intervention system should you understeer or oversteer past the limits of adhesion as nick pointed out. Your car handles the same under normal driving conditions regardless of what state DSC is in. How the car responds to loss of traction in any of the four wheels is a different thing altogether.

So in short: you don't know what you're talking about and you should be keeping dsc on.

^( last paragraph note to the OP)

Originally Posted by E46Cherry

Nice try. Did you even read? That was a reply towards a post regarding Porsche's not having DSC, and a guy mistaking DSC for DCS (acronym spelling). And I said I was driving 50 mph at most in the heavy rain. I think you did a great job making yourself look like an idiot.

Edit: and I mentioned not checking tire threads prior to driving. Again, if you have nothing intelligent to say, I suggest not making yourself sound like a moron.

relax man, i know that the DCS post was in regards to the porsche, i didn't feel like double quoting, it was understood who i was talking to. 50mph in the heavy rain, yet you still turned DSC off, without knowing the conditions of your tires. for someone who does 80-90mph on the regular, it's unlikely that they drive as safe as possible when it's raining. on top of that, you don't understand how DSC works, as pointed out by gentlemen above this post.

Originally Posted by E46Mango

^( last paragraph note to the OP)

The last sentence? Yeah like I said on a previos post, I didn't know what DSC was, aside from what it stood for. In my experience last night AND given the tire treads I have, it just seemed to handle better and felt like a safer drive. But maybe it was just the luck of the draw.