Ahh, I sort of expected that type of reaction.

Slick tires with fairly round casings that are properly designed for their application will not hydroplane at sane speeds. Adding a tread pattern to these tires (for on road use) will only decrease their performance. This is counterintuitive and hard to fathom for some, though it sounds like many of you have experience with it.

MotoGP (and other racing motorcycles) change tires when it rains because they want a better suited compound, not necessarily because the dry tires hydroplane, although they are definitely seeing rather insane speeds, so I'd guess they might hydroplane as well in standing water. The intricacies of how and why wet compounds differ from dry compounds would make for a nice senior project.

Wet tires use super soft compounds for more grip from their smaller effective contact patche while relying on the water to keep temperatures in check.

And no, a treadless tire in the wet is ALWAYS a bad idea. The real reason slicks hydroplane is beacuse of the film of water that forms between the tire and the tarmac, rendering that sticky compounds useless. Added to that fact that wide racing tires have such low contact pressures, there's simply not enough pressure to effectively have a sufficient area of the contact patch squeeze away the layer of water to achieve sufficient tire contact with the tarmac to maintain acceptable grip. That's why excessively wide tires without sufficiently deep and well designed treads struggle to avoid aquaplaining.

Quote from skiingman :

MotoGP (and other racing motorcycles) change tires when it rains because they want a better suited compound, not necessarily because the dry tires hydroplane, although they are definitely seeing rather insane speeds, so I'd guess they might hydroplane as well in standing water. The intricacies of how and why wet compounds differ from dry compounds would make for a nice senior project.

Uhm, you're not saying that MotoGP wet tyres are actually slicks, are you?

Quote from TheDeppchef :

Uhm, you're not saying that MotoGP wet tyres are actually slicks, are you?

No, obviously they aren't.

I'm saying that the biggest difference between drys and wets is the compound. You can cut treads into drys and they will still be awfully slow in the wet.

Quote from Jamexing :

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And no, a treadless tire in the wet is ALWAYS a bad idea.

If the conveyance in question is a performance automobile or motorcycle, that is quite correct. Not the case in a variety of other realms.

Quote :

That's why excessively wide tires without sufficiently deep and well designed treads struggle to avoid aquaplaining.

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My personal experience suggests that tread depth is the most important factor with liquid water, in that a full depth crap tire will often perform much better than a great dry/wet tire that is more than a few thousand miles old. With frozen water, good siping and the narrowest practical section width seem to do the trick

As shown by the tiny tyre widths used on ice rallies.

Does anyone know why F1 Monsoon tyres are not noticably narrower (that I can see) than the slicks? Sure, they're treaded, and of a different compound, but why not make them narrower to avoid aquaplaning even if it's at the expense of OUTRIGHT traction?

Quote from tristancliffe :

Does anyone know why F1 Monsoon tyres are not noticably narrower (that I can see) than the slicks? Sure, they're treaded, and of a different compound, but why not make them narrower to avoid aquaplaning even if it's at the expense of OUTRIGHT traction?

Haven't seen those tyres up close, but according to regulation that I got open in a tab to your right (*points*) complete wheel width has to lie between 305 and 355mm in front and 365 and 380mm in the rear. I say that if there was a large difference in width it would only be noticeable from TV for the front tyres and only if you had something to compare it to right away (preferably a set of normal tyres).

It's possible that tyre designers think they can get the groove (now I got a mental image of a tyre designer playing guitar with a wah-wah pedal) designed well enough to get the water out in time and provide maximum contact patch at the same time. I suspect they are probably wrong most of the time and the drivers are lucky we haven't seen those tyres used all that much.