So, attended the German ADAC safety course yesterday with my G35C. One of the exercises involves driving over a watered-down plastic surface to simulate icy conditions. After the front tires cross, a hydraulic plate moves the rear wheels 6" to the left or right causing a tailspin. No problem, VDC is supposed to help right? I did 2 360's while holding the wheel straight. Next time around, turned off the VDC and did 2 more 360's. Ok, expected that. So, the next time as I brake traction, take control and attempt to correct with countersteer - no luck! tires are locking and unlocking attempting to correct as I correct. 4th try VDC off, same thing. 5th try I managed to stay on the track, but still got pretty sideways, countersteered, saved it, and then corrected it going the other way. 6th time, machine malfunctioned, and it was on to another exercise. So, me and another tricked out 325i "sport car" asked to the Instructor, WTF?
He explained that wider sport tires with ABS are worse than the 15 inch little celica tires for ice and snow. How is that possible? I have VDC and it is supposed to compensate? Nope, when the back end steps out, the side pressure on the front tire(centripal force) overwhelms the ABS causing them to lock up, this reduces the side pressure breaking the front wheels loose as well, allowing for less traction and another 360 or meet with stationary object.
His suggestion would be to use narrower tires with snow tread(maybe the KDW's) for winter driving. The justification is that wider tires while providing additional traction in the dry, provide less pounds per square inch of pressure in reduced traction events than a corresponding narrower tire(think of pounds per square inch of a 4" wide tire vs 7" tire with the same weight vehicle.)
So now what to do ?
I was greatly dissapointed that my "high speed safe car" was embarassed by a 10 yr old celica. Granted I did the speed slalom, emergency brake and avoid an object while still steering were all above par, but this makes me wonder.
Options -
1) Don't drive it under extremely wet, slightly icy, snow conditions
2) put all weather tires on and pray
3) Screw it, ride as fast as I want, I've got like 5 airbags anyway...
Your thoughts?

 

get a winter beater, or kill yourself

 

I don't understand what you are trying to say..... driving over wet plastic surface = no traction. VDC won't help you if all four tires have no traction, neither will fatter or thinner tires. Maybe if you were riding on suction cup surfaced tires you'd get some traction.

Thinner tires will give you more traction in snow, but why in the world would you put skinny winter tires on a sport coupe? Buy a $500 beater and be done with it. Winter & Sport don't go well together. Honestly though, I don't see how thinner tires will give you more grip on a wet plastic surface.

Fatal flaw? yeah, try not to drive on plastic roads all the time and keep VDC on.

 

If this plastic actually does simulate ice well, then chances are, our summer tires are not going to respond well to it. And I'm not sure I trust this "simulation" of causing the rear wheel to move out 6 inches or so. When a car turns, the outside front wheel takes on a large proportion of the load naturally. The rear wheels follow the front wheels, but at a smaller radius(larger wheelbases equates to a tighter rear wheel radius). As a result, much of the car's weight will have a natural tendency towards the outermost part of the car, which will be the front outside corner. Ice doesn't normally move to the side underneath your car. When you typically lose control of a vehicle, the tendency of the rear end is to simply want to continue in the direction it is already travelling. Pushing the rear end to either side makes the rear now want to move laterally. I can only speculate, but this is not something I'd expect to see any engineer try and compensate for. The only condition I can see something like this happening is if you get broadsided towards the rear of the car(even light impacts can cause a spin if the vehicle is moving fast enough. By the time VDC can actually kick in, an accident has already occurred. I doubt VDC at that point can do anything to really stop a spin. From the times I've encountered VDC actively working on my car, it tends to try and prevent a loss of control. A sudden movement created by an outside force is not what VDC is designed to control.

As far as tire width, wide tires in the wet are generally worse because water can't evacuate to the side of the tire quickly enough. Think of trying to waterski with water skis and then trying to water ski with iceskates. The iceskates will dig deeper into the water. Thinner tires will do the same which will allow a wheel to remain in contact with the ground at higher speeds. While wide tires may not have circumferential grooves and such, it can't pump it out passed the outer tread as quickly as a smaller tire. On snow and ice, a thinner tire can indeed allow a tire to dig more into the snow/ice. Though, width in that of itself will likely result in a lesser difference on ice as ice gives very little compared to snow.

 

you are dead on... abt wider tires causing more problems... the thinner the tire the better in snow.

if i was in your place.. i would get a winter beater... but if that is not possible... then get a winter setup and drive very very carefully... another thing going aginst us in the winter is that the G's are rear wheel drive cars, which are worse in the snow as compared to FWD.

 

So you were driving on simulated ice with your high performance Pilot Sport summer tires and you think that the car has a flaw? People do buy winter rubber for a reason.

 

It's well known that in the winter skinny tires fair better than thick ones.

I hope that if you plan on driving in the winter, that you are buying winter tires for your car??

 

Its not really a flaw if it was designed to be this way. The G35 was meant to be a sports car so of course wet weather traction isn't its strong point. Thats why they have the G35x

 

Take a hard look at any 400hp rally car (EVO, WRX, etc) and take notice to just how small and narrow the tires when they're racing on snow covered tracks compared to what they run in non-snow conditions.

I don't think they're is ANY dangerous flaw in the G/Z. The correct tires are key.

1) No car or truck does fine on the ice. Ice is ice and it's damn slick. It doesn't matter if you have VDC, ABS, AWD, or 4WD or any combo.

2) Only an idiot would venture out in snowy/icy conditions in a G/Z with wide performance rubber. At a minimum, you should has A/S tires and if you live in a snowy region, narrower snow tires are key. I can assure you a G35 with snow tires will do better in the snow than an AWD Subaru on A/S tires.

3) Wide high performance tires are good for lateral G's, but **** poor for evacuating rain or slicing thru the snow.

No electronic nanny can save a stupid person from driving too fast for conditions or with with wrong tires.

 

the G sucking in even mildly sleety/icy/snowy conditions has been beaten to death and is easily proven by any member who lives in the northern half of the country who has ever tried to drive the G in these conditions. You don't need a fake plastic road and its hardly a flaw. Its a rear wheel drive sports car with fat low profile summer tires ...

get some winter wheels/tires or a winterbeater. end of story.

 

I think the "fatal flaw" has less to do with the vehicle and more to do with your lack of understanding when it comes to driving on the ice. Not trying to insult or anything, but I'd consider this common sense and not worth crying wolf that there's a serious problem with the car.

 

coming back from Dallas a few weeks ago, I hit a rain storm. A part of the interstate was pooling alot of water. I was able to maintain 60mph without hydroplaning (70mph speed limit). That was until I passed an 18wheeler. As I was being buffeted as I passed, another gust of wind hit my car. The car rotated to about 30 degrees I'd say. We were looking at the median and wall. I didnt to anything but let the VDC do its thing. The rear ABS modution was very pronounced. It righted us without leaving the lane, which would have been tragic to the right (semi) and questionable to the left. VDC saved us some serious injury. So, whatever flaw it may have, it wasnt fatal for us. I was thankful to have it.

I've found the GC wont even move in alittle snow with summer tires. Not even leave its parking space, so travelling without winter tires in the snow is kinda of a moot point. You'd know before you started moving that you really shouldnt be out in those conditions without the right tires. I've gotten home in *ICE* one day (freak storm, no choice). I passed many sports cars that were nosed into curbs and medians. I think the vehicle control systems the G are above average for sports cars. What I've personally seen has convinced me of it.

 

I think if you were to re-simulate the situation with four winter snows on the car the outcome would have been different. I live in the Northeast. We do from time to time have some significant snow accumulations. Attempting to drive the G in snow with summer performance tires is completey unsafe. The car will go no where, and you risk damaging your car, injuring yourself, and possibly some innocent party as well....... Snow tires and conservative driving makes the most common sense.......A taller narrow snow seems to give the best overall performance.
I have never had a problem with heavy rain/flooding situations, with either the summer Pilots or my Dunlop M3 snow sports, the VDC always did its job.

 

I think the "fatal flaw" of this thread is the lack of using the search funtion.
Rear wheel drive + Summer tires in winter driving (snow/ice/etc) = Asking for trouble, period. Nothing new here.

 

I think this was a mis-leading post.

I expected to hear about driving over a bump and the car blowing up or somehting????