ryoung

The back tires run in the path cleared by the front's, unless the water is very deep.

Bollinger

You're wrong, you do not usually hydroplane. The water usually gets squeezed into the channels in the tire or goes into the compound of the tire.

If you were running on a film of water, you'd have very little traction.

I mean come on, if you hydroplaned no matter what, why would F1 drivers switch to rain tires? I mean if you were hydroplaning and only working with the suction of the surface tension of the water, wouldn't you want a slick so you'd have maximum tire in contact with that thin film?

Bollinger

When no acceleration is being applied, FWD=RWD=AWD=0WD.

sly1

<B>The reason Audi owners feel their car is safer in the wet is because:

1. In AWD cars, (while having the foot on the accelerator) the grip used to move the car forward is distributed between all 4 wheels, therefore leaving more grip available to prevent lateral movement.

2. Most Audis mentioned above are not using such aggressive low profile, wide summer tires as the M3, therefore giving more grip in the wet. If the Audis were wearing rear M3 tires all around, the sensation of grip would be diminished significantly in wet conditions.

In other words, AWD cars give more traction (i.e. under acceleration) but not more grip (i.e. braking) than RWD cars.
They do not create traction/grip, they just use it better to move the car forward and to avoid lateral slippage.</B>

Reggie3

Good advice - it's the same as if you were on ice

mm

...that you get some traction back before something bad happens.

mm

...depends on tires, car weight, water depth, speed.

mm

...and attempting to do so will only make matters worse, in so far as it's more likely to INCREASE the duration of the hydroplane and unsettle the car when traction is regained.

JDBlueAudiS4

I preface this saying my car has true all season tires and does have quattro. So what I am saying applies to this setup:

Accelerating while in a hydroplaning Situation :
- Almost as bad as breaking.

Decellerating while Hydroplaning :
- Wasnt to bad but felt lack of control if I need it to avoid something

Keeping current Speed :
- Not to my suprise, this was the best situation, once the car reached the other side of the water i didnt feel off balance and during I didnt feel any problems and felt like I had enough control if I needed it.

Braking:
- Ok bad idea, I did start to enter a Spin but pulled out as I reached the dryer spot.

Up in PA we are getting killed with rain so I thought I would go out to an empty parking lot I know about and try this out. It has a Long strech and the middle collects enough water for my experiments. While I never could feel all 4 wheels were in hydroplane, what I mentioned aboved probably applies to 1-3 wheels that are hydroplaning.

I end this with saying, this was all done in a fairly controled environment so results on different types of roads will be different but it does to rapid change in rpms/speed while you think you are hydroplaning is a bad idea. I did also find that the higher the RPM's are (did most of the testing in the 3k-3500 range) the more control you have while your hydroplaning. I did one run with ~4500 RPMs and I felt alot more control. Hope this helps guys. I was fortunate enough that the rain gods decided to give me lots of rain today, however I dont think I am the only one. Just remember Be Safe!

mm

...rpm has nothing to do with anything. If anything you can brake a little and can steer the wheels in the direction the car is traveling (i.e. generally hold them where they were when the hydroplanning started), beyond that you're basically just hoping that at some point you regain traction/control and then that you have time to do what you need to do from there.

This is basic vehicle dynamics, quite simple really, no need to "test". Trust me, this is correct.