Originally posted by WD40
An underinflated tire will be much more likely to hydroplane and is extremely dangerous.
When you hit standing water in an underinflated tire, the center of the tire will deflect and become concave "cupping",
and will end up floating on top of the water=hydroplaning.
By increasing the psi in the tire, you will negate the "cupping" effect.
1) It will have a narrower and shorter contact patch.
^^^Results in greater psi between the tire and the road.
2) The profile will be more round, and will not be able to deflect as much.
^^^Read, resitance to cupping.
3) It helps keep the grooves in the tread open so they can channel water out from under the tire.
^^^Again, a underinflated tire will deflect, and many times close off the grooves that channel water.
OK...just to verify...the experts say the same thing:
yeah, you are correct I know from experience on a trip to/from San. An....it rained HARD. I was in my Probe, I floated from the far left lane to the grass on the right shoulder.....all because my psi was low in my two fronts.....
I was so messed up and shaking I had to sit in a parking lot for an hr to convince myself it was safe to drive.....