Floating car

[learner]

Ive just wrecked a new car by aquaplaning across a road into an old farm building. Did I realy float on water? It was only 5mm deep! All went quiet and I slid, as though on ice, for about 30 foot and slammed into said building, broadside at about 25mph.
Very wierd.
Could any of the big brains give me a easy to digest explanation of how a big car (m5) can float so easily and how do you go from not floating to floating? Tyres are good, only done 7k miles.

[WillM]

This link will send you to a site that explains Hydroplaning.

http:// www. engr.pitt.edu/ssc/hydroplaning.html

Just type the url into your browser without the spaces.

For people who don't want to bother, I copied the text from that web site below.

According to Smart Motorist, Hydroplaning occurs when water on the roadway accumulates in front of your vehicle's tires faster than the weight of your vehicle can push it out of the way. The water pressure can cause your car to rise up and slide on top of a thin layer of water between your tires and the road. While hydroplaning your vehicle rides on top of the water, like a water skier on a lake. In less than a second, your car can completely lose contact with the road, putting you in immediate danger of sliding out of your lane. This usually happens at higher speeds, over 40 miles per hour. Try to imagine your vehicle traveling at a high rate of speed on a sheet of ice: that image approximates what will happen if you try to brake or steer while hydroplaning.

[learner]

This link will send you to a site that explains Hydroplaning.

http:// www. engr.pitt.edu/ssc/hydroplaning.html

Just type the url into your browser without the spaces.

For people who don't want to bother, I copied the text from that web site below.

According to Smart Motorist, Hydroplaning occurs when water on the roadway accumulates in front of your vehicle's tires faster than the weight of your vehicle can push it out of the way. The water pressure can cause your car to rise up and slide on top of a thin layer of water between your tires and the road. While hydroplaning your vehicle rides on top of the water, like a water skier on a lake. In less than a second, your car can completely lose contact with the road, putting you in immediate danger of sliding out of your lane. This usually happens at higher speeds, over 40 miles per hour. Try to imagine your vehicle traveling at a high rate of speed on a sheet of ice: that image approximates what will happen if you try to brake or steer while hydroplaning.

Thanks WillM. The water was from an overflowing drainage ditch on the side of the road. That would explain it building up faster than my tyres could push it out of the way. I think I was only doing 25mph, maybe a bit more, but was on a bend. I had no chance to brake or steer, but I imagine it would have made no difference. It felt like I was floating.

[Smackety]

I have never had that problem with good tires. With old bald tires however...
You might want to think about suing the tire manufacturer. Tires should be rated for more than 5 mm of water at 25 mph.

ETA: you wrecked a brand new M5? Isn't that a capital offense?

ETA2: Are you okay?

[learner]

I have never had that problem with good tires. With old bald tires however...
You might want to think about suing the tire manufacturer. Tires should be rated for more than 5 mm of water at 25 mph.

ETA: you wrecked a brand new M5? Isn't that a capital offense?

ETA2: Are you okay?

I will certainly be looking into it.
I am fine, it was the passenger side that took the hit. The whole length of the car is damaged. Luckily I had no passengers. Got to say it did shake me up a bit. Its with the recovery people at the moment may even be a write off!

[macdoc]

I've had it happen tho no accident resulted. Decent tires but the water pooled in the slight depression of the highway track worn by trucks etc - just like glare ice - I just rode it out with no sudden attempts to brake hard or steer and the tires settled but it was eerie.

I suspect the OP case the tires were broad and likely weight forward ( braking ) and perhaps slightly downhill - it all conspires........ tho full broadside sounds a bit faster than 25 mph :garfield:

Tires are designed to channel water aligned with the tire - not when sliding sideways - a rounded shoulder on the tire would contribute to the hydro planing in that orientation.

Some mud on the road would contribute.

[learner]

macdoc. Sounds like you were there!
Broad tyres..very
Braking..gently
downhill..very slightly

No mud though. We have had a lot of rain and the roads are washed clean, I didnt notice any mud.

[macdoc]

That will do it - glad it's just the car tho. :thumbsup:

[rjh01]

I hope you had insurance.

[learner]

I hope you had insurance.

I did thanks. And am I glad I did. Seems its a complete write off. Structural damage throughout. I didnt think I hit the building very hard at all. Maybe Il buy a volvo next. :)

[69dodge]

I don't know for sure, but I'd imagine that a car like an M5 would come with tires that are optimized for very good traction in dry conditions, at the expense of somewhat poorer traction in the wet.

Racing tires ("slicks") have no grooves at all in their tread, which is terrible in the wet, but gives the best traction otherwise. More rubber in contact with the road. In the wet, grooves give the water somewhere to go: water on the road near the center of the tire doesn't have to be pushed all the way to the edge of the tire in order to let the tire touch the road; it can just go into the nearest groove.

[Olowkow]

I drove a cab one summer in Pittsburgh and they made a big thing about hydroplaning. They did what they called "microsyping" to the tires, which is putting little slits across the treads, and claimed this prevented hydroplaning. It never rained all summer, so I never got the chance to try it out.