Snow!

[thomas]

update on the C-Class:

today he was towed out there by his neighbour with a passat. FinalGear Top Tip: Snow vs. Summertires - dont. he slowly crawled to the next merc-dealer...

-btw: no problems with rwd over here. made ~120km today, hills up and down, more or less snow.. dtc working several times but no difficult part.

 

[prizrak]

The ESP can't be compeletely turned off on that Merc and the braking function works always. You can actually smell the brakes when drifting on an empty field for a while.
As mentioned before rocking back and forth is the best method to get clear if you're stuck in snow.

I know but it doesn't make it suck any less in snow. In my car I can turn off my TC/ESP and spin all 4 wheels which is quite a bit of fun when you are stuck and irritated

When you beached your car on snow, a good trick is to collect a few people and let them sit in your car, on the mudwings or in the boot. The more, the better. That hunks the car down and compresses the snow and maybe, when the folks have gotten out of your car, gives you enough air to get out of the mess. It worked for me once.

Interesting idea, I ended up borrowing a shovel from someone and digging myself out.

 

[Blind_Io]

^Any car can get stuck. I got stuck in a parking spot with my AWD, doesn't help much when snow is up to your grill and the car is beached :'(

True, but with true 4WD and a locking diff combined with deep-tread off road tires and a 4,600+ lb vehicle it takes a hell of a lot more than a flat road and a bit of snow to do it.

Anyone actually try that rubber floor mat trick? All it does is shoot your floor mat down the nearest storm drain or into a snowbank.

Putting weight in the car for traction works, if you have a snow shovel pile snow on the roof and boot lid.

 

[Smurfen]

Awesome!

video:

http://www.vg.no/bil-og-motor/artikkel.php?artid=579038

 

[prizrak]

True, but with true 4WD and a locking diff combined with deep-tread off road tires and a 4,600+ lb vehicle it takes a hell of a lot more than a flat road and a bit of snow to do it.

Anyone actually try that rubber floor mat trick? All it does is shoot your floor mat down the nearest storm drain or into a snowbank.

Putting weight in the car for traction works, if you have a snow shovel pile snow on the roof and boot lid.

Well yeah a real off road vehicle would be way better. Not sure if it would shoot the floor mat, I was able to use cardboard like that before and it didn't fly anywhere. Putting kitty litter under the tires helps as well, though I wouldn't wanna stand behind that car

 

[AiR]

Wohoo traction control! It's slippery today, especially at the post drive in u-turn thing.

 

[sonza68]

Interesting idea, I ended up borrowing a shovel from someone and digging myself out.

I carry a shovel in my trunk during the winter for this reason. I also keep a bag of kitty litter in there for when I get stuck on ice.

 

[Blind_Io]

Well yeah a real off road vehicle would be way better. Not sure if it would shoot the floor mat, I was able to use cardboard like that before and it didn't fly anywhere. Putting kitty litter under the tires helps as well, though I wouldn't wanna stand behind that car

The only times I've seen anyone actually try this it either flipped the mat out or melted through it. I think that whomever came up with this idea probably lived in Florida.

 

[Pry]

I know but it doesn't make it suck any less in snow. In my car I can turn off my TC/ESP and spin all 4 wheels which is quite a bit of fun when you are stuck and irritated

"Electronic limited slip differential systems use speed sensors, anti-lock brakes, and microcomputers to electronically monitor slipping. If any of the wheels on an axle is rotating unusually faster than the others, the computer will assume that it is slipping and will briefly apply brakes to it, slowing the spinning wheel down and causing the opposite wheels to gain speed and keep traction."

Can't see how it doesn't make it suck any less in snow.
Sure it's nicer to have torque on the wheel with most grip.

 

[Blind_Io]

But if none of the drive wheels have grip you have just turned the car into a brake-toasting machine.

 

[frankiess]

Up here in Soviet Finland, where we're too poor to have our driveways cleared we have sand deposits near parking lots to help in such situations. And even that doesn't help if you have a low clearance RWD car parked tightly. .. A situation which I somehow find myself in too often.

But then again, I know when to quit and look for help.

 

[matyas]

But then again, I know when to quit and look for help.

Are you sure you are living in Finland? The land of the shy rally drivers?

 

[prizrak]

"Electronic limited slip differential systems use speed sensors, anti-lock brakes, and microcomputers to electronically monitor slipping. If any of the wheels on an axle is rotating unusually faster than the others, the computer will assume that it is slipping and will briefly apply brakes to it, slowing the spinning wheel down and causing the opposite wheels to gain speed and keep traction."

Can't see how it doesn't make it suck any less in snow.
Sure it's nicer to have torque on the wheel with most grip.

What blind said. Basically in low traction situations such as snow spinning wheels is one of the ways you build up some traction. You can see that most readily in WRC, they are always going around turns sideways because that lets them maintain some semblance of grip.

 

[Jupix]

prizrak This time you're just wrong, ok? I don't know anything about rallying (I'd guess powersliding around corners decreases the chance of understeer mid-corner or something) but I know a lot about getting myself unstuck in snow and wheelspin is the absolute worst thing you can do, because of 2 things.

1) Wheelspin effectively nulls traction. In other words when you spin the tires, you lose all the grip that you might've otherwise had. This is most apparent in an incline where if you gently roll yourself up the hill using torque and grip, you will eventually get up, but if you spin the wheels you start rolling backwards.

2) When you apply too much power and start spinning the tires, you start digging into the road surface. And when you've got snow, what's underneath that snow? Ice. And which do you prefer for grip?? Avoid wheelspin and it's possible you might be able to use that snow layer for traction, but blow it off and you're ice skating, literally. Most winter tires work better on snow, than ice. Wheelspin on snow and ice is not "building traction", it's "demolishing traction", at best.

And anyway, wheelspin will destroy your tyres, especially studded and eventually, unstudded too.

In fact the only scenario where I can see your theory working is a light drizzle of snow in above zero temperature, where there is asphalt below the snow, and that is a very rare scenario indeed. (At least in the so-called proper winter countries as my fellow countrymen tend to put it, although I find that term slightly offensive.)

Although I'm managing without, I didn't have to make an abrupt maneuver or emergency stop, yet.

Please be aware you won't be doing any of those with winter tires either. The best of winter tires aren't good enough at stopping/swerving to avoid a crash if you don't see it coming a mile away, that's why driving in the winter is considered a bit of a Russian roulette. Mostly winter tires are for driver convenience in ordinary situations, in extreme conditions. They're pretty much as useless as anything else in emergency situations.

 

[LeVeL]

prizrak This time you're just wrong, ok? I don't know anything about rallying (I'd guess powersliding around corners decreases the chance of understeer mid-corner or something) but I know a lot about getting myself unstuck in snow and wheelspin is the absolute worst thing you can do, because of 2 things.

1) Wheelspin effectively nulls traction. In other words when you spin the tires, you lose all the grip that you might've otherwise had. This is most apparent in an incline where if you gently roll yourself up the hill using torque and grip, you will eventually get up, but if you spin the wheels you start rolling backwards.

2) When you apply too much power and start spinning the tires, you start digging into the road surface. And when you've got snow, what's underneath that snow? Ice. And which do you prefer for grip?? Avoid wheelspin and it's possible you might be able to use that snow layer for traction, but blow it off and you're ice skating, literally. Most winter tires work better on snow, than ice. Wheelspin on snow and ice is not "building traction", it's "demolishing traction", at best.

So by your rationale the second your wheels start to spin you should just stop and call a tow truck?

driving in the winter is considered a bit of a Russian roulette. Mostly winter tires are for driver convenience in ordinary situations, in extreme conditions. They're pretty much as useless as anything else in emergency situations.

You must be using r-comps as winter tires then! Of course any tire on snow wont have the grip that it would in the dry but calling winter tires useless in an emergency situation is just ignorant. The Russian roulette comment just means that you're scared of driving in the snow. You get in, and you drive. Plain and simple. Use some common sense (which you should be doing in any conditions) and you'll be a-ok.

 

[Pry]

Well, the Mercedes doesn't need LSD in situations like the C-class had as it has the electronic LSD. On performance oriented driving it's a different case and that's why AMG's and M's has a mechanical LSD.

When you're stuck in deep snow the first thing you should try to do is try to reverse out. If your wheels just start to spin you should start rocking it back and forth with the clutch. It's sort of a same effect you have when you're swinging. When you keep doing it in the right pace you're probably going to get clear. This is a method they teach in Finnish driving schools and if my memory serves me right they used it in top gear polar special also.

If you just continue spinning the wheels they are going to dig deeper and eventually you are beached on your cars bottom with no weight on the wheels. Then it's time to find a shovel or get help.
I've been in situations like this countless times with a car and a snowmobile and spinning the wheels/track is always wrong.

If you're stuck on a hill in low snow conditions like the C-class were spinning the wheels is still wrong. The snow/ice under your tires is going to start melting and there's really nothing worse for grip than water on snow/ice.

The correct thing to do is try to reverse and find a grippier spot and then try to get up with speed.

Spinning the wheels is also wrong from the physical standpoint because static friction is larger than kinetic friction.

Here's a video from fifth gear, check the part when Tiff is trying to get up that icy ascent:
[YOUTUBE]http://www.youtube.com/watch?v=K3m24bjkfg0&feature=related[/YOUTUBE]

In fact the only scenario where I can see your theory working is a light drizzle of snow in above zero temperature, where there is asphalt below the snow, and that is a very rare scenario indeed. (At least in the so-called proper winter countries as my fellow countrymen tend to put it, although I find that term slightly offensive.)

I'm not sure would that work either as the temperature of the road is still bellow 0 Celsius degrees and when a part of the snow melts it's going to turn immediately to worse.

 

[public]

So by your rationale the second your wheels start to spin you should just stop and call a tow truck?

No, you should use your throttle in such a way that you don't spin your wheels.

What blind said. Basically in low traction situations such as snow spinning wheels is one of the ways you build up some traction.

A friend once floored the throttle on his Lada, as he got stuck on an ice track. The speedo went up to 180km/h as the car was still sitting where it was, spinning its wheels.
He must've built up a shitload of traction.

 

[Jupix]

So by your rationale the second your wheels start to spin you should just stop and call a tow truck?

Was addressed above by someone else.

You must be using r-comps as winter tires then!

Don't know what that words is in my language but I have experience of a wide variety of tires on a wide variety of vehicles, on a wide variety of road conditions plus the theory taught in all driving schools in my country, all of which I base my opinion on. I'd call mine a reasonably informed opinion.

Of course any tire on snow wont have the grip that it would in the dry but calling winter tires useless in an emergency situation is just ignorant.

It's not, it's a realization of the facts and physics involved. I was just in a crash in my car, remember? With brand new winter tires, and basically the best models available, with ABS. I'm telling you, when you've got only a couple of seconds to react, there's absolutely nothing you can do to avoid the accident, the mass of your vehicle won't have the time it takes to change direction on a slippery surface, no matter how good your tires are, let alone come to a stop.

Remember, we're talking about an emergency situation. By definition, you won't have ample time or space to play around with the grip increase from winter tires.

The Russian roulette comment just means that you're scared of driving in the snow.

I suppose I am a little, for the reason mentioned above. You, on the other hand, seem to me to suffer a bit from hubris. I do "just get in and drive" all the time. And I think everyone should be a little scared of slippery roads, we'd have better equipment, less accidents and therefore less police breathing down our necks when we're playing in the snow not on the road.

 

[Posmo]

^Why was your friend in 5th gear if he was trying to get unstuck? @public

 

[public]

He didn't, he was being a Lada redneck.