Snow/slush - deflate or not?

[RatLabGuy]

Given the inevitable 12" of snow and impending doom , a cowroker and I were "debating" whether it would be better to drive w/ tires deflated a little or not. He says, deflate to increase traction, liek you would offroad. My thinking is, this is different - you want to kind of "cut" through the crap, rather than grip around it, being deflated adds contact area which would be worse, not better.

Thoughts?

 

[shawn]

If it's less than 18", you want normal air pressure. Decrease contact patch, so you cut through. That's especially important when you're talking about 1-2" or less.

 

[6BangBronk]

Not to mention, stiffer sidewall with full air to support you on turns for quick decisions.

 

[BlackSheep]

deflating your tires results in heavier loading on the shoulders, and a square or dog-boned shape footprint. The center of the contact patch becomes less loaded and the slush is directed to the center of the tire (by the heavily loaded shoulders). This can result in an increased chance of hydroplaning as the slush will lift the not-so-heavily loaded center section (of course depends on speed), seriously reducing your footprint.

By keeping your normal pressure, you have a more rounded footprint which acts more like the bow of a boat, directing the water / slush around the outsides of the tire.

Obviously, if you're only talking about lowering the pressure by a few pounds, the difference would be less noticable than if you lower by 10 pounds.