BMW's sliding in the rain....

[Threetwoeight]

Fatter tyres get on top of water easier than thin tyres. (thin tyres slice through the water) Thats why it seems that older lesser cars handle puddles better. My first two cars had 165 R13 tyres and I used to steer in to standing water to spray. Got a few scares with 205 R15 and now I show a little respect to water but still enjoy the ride.

On modern cars you will notice that the Cruise control will cancel as soon as any wheel slip is detected. (Closing the throttle suddenly on slippery surface could be a problem) Also some cars the cruise control will not activate when the Traction control is switched off.

This said. I will not drive with cruise control in any conditions that need extra attention.
Remember this: When the front wheel hit standing water the car slows down.... The cruise control will want to regain the set speed (it does this gently!) Then the rear wheels hit the water, will also slow down the car. The cruise control want to maintain the set speed, will always increase the throttle position gently but after a few seconds you would get full throttle if needed.... unless traction broke before this. Which will cancel the cruise control, closing the throttle abruptly. Making a bad situation worse.

Also remember that you almost never hit water square with both front wheels never mind all 4, So hitting water with one wheel before the other will cause the car to want to rotate (like using only the left front brake) and if the road is slippery .....

Also water running over the road comes from next to the road bringing all the dirt mud rubber balls and stones with it and every car that passes trough spreads it after the stream of water.

Diesel and oil spills are very common and I don't think any tyre, car, traction control setup can manage.


Sorry for the long post, and don't want to sound like a professor.

My car also spent Christmas at the panel beaters:banghead:

 

[andreas]

Hi Guys,

got a E46 318 Touring 2004 Mod, just checked the manual, on page 68 it states:

"Do not use cruise control on twisting roads, in heavy traffic which prevents a constant speed from being maintained or if the road surface is slippery from snow, rain, ice or loose due to stones, sand."

So the engineers are aware of it, but don't seem to have a solution to it yet. Maybe the new F30 has the solution?

 

[Threetwoeight]

To sum it up:
Front wheels hit water at slight angle, slowing car down and putting rotational pressure on car.
Cruise control increase power to maintain speed
Rear wheel hit water at same angle, slowing the car and increasing rotational force.
Cruise control increase the power,
Traction breaks (rear wheels light up for a milisec)
DSC responds by shutting down CC (closing the throttle) and start braking the faster rear wheels.

Looks like someone is yanking the hand brake up here.

Nah I am scaring myself.
No traction control for me thanks, (yes I cant afford it) but at least when something goes wrong I learned something from it for next time, like don't lift accelerate a little.

 

[netercol]

guys, manufacturers would never let a car out the door if it had possible UNPREDICTABLE behaviour in any conceivable condition..(not talking about unpredictable road conditions) ,they try to avoid liability at all cost.

read some expert opinions..

http://roadsafety.co.za/2010/02/15/...o-driving-with-cruise-control-in-wet-weather/

http://www.hoax-slayer.com/cruise-control-warning.html

 

[Coisman]

imp:
All I can say is next time you start to slide, drop the clutch, gear change to a lower gear,
hit the throttle, and go out in style!

 

[BMW M]

imp:
All I can say is next time you start to slide, drop the clurch, gear change to a lower gear,
hit the throttle, and go out in style!

Coisman, mines an auto, and the moment I felt it sliding I started correcting, dropped it into 'Sport' and floored it... Then the dash lit up like a Xmas tree... DSC didnt like me trying to drift her.... lol