hydroplaning

[Huw Powell]

> IMHO this theory that hydroplaning depends only on the pressure in the 
> tires, and is independent of tread design and contact patch, just 
> doesn't make sense.
> 
> Think logically about what happens. If you have a vary aggressive tread 
> with deep grooves, water in all its forms, wet, snow, mud, can squeeze 
> out through the grooves and the tread will make contact with the pavement.
> 
> Taking it to the extreme, a very narrow tire will not hydroplane as 
> easily as a drag racing slick.
> 
> If the above is wrong, my thinking on this subject has been wrong for 
> the last 45 years so I hope someone can show me some experiments that 
> prove it's wrong :-)

I think this is the way that rule of thumb formula works.  At those 
speeds, as long as there is a layer of water, the tire can no longer 
penetrate it fast enough to make any contact - tread pattern does not 
matter because the "contact patch" is doing the hydroplaning.

While I'm sure there might be some small variations (it sounded like a 
rule of thumb, after all, not "hard" physics), it does make sense.

Think of what happens when you hit a puddle, say, at least 1/2" deep - 
no matter what the tire is, if you're going fast enough it simply rides 
on top of the water.

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/