Snow tire pressure - higher or lower?

[gale]

Got another 6" overnite & still snowing. Wife took the truck, had to put a spare set of Blizzaks on mine this morning. Do I run them higher or lower than regular tires?

Thanks

[colo525i]

I've always used the ratings in the manual, which show higher (29/35)? for Q rated (most dedicated snows are) than for all seasons or "summer" tires. Just check the tire rating and there should be a listing.

[Tiger]

31 Front and 35 rear is what I do.

[Black 535i]

Will give you a larger contact patch with the ground but realize that you will not have handling as before. I watched a show about two guys driving across the Antarctic and their tire pressure was never over 2-5 psi!

[pingu]

On Top Gear they also used lower pressure when on snow. I guess that a lower pressure allows the tyre to deform to the shape of the snow.

Also, I seem to remember that normally, the problem with low tyre presures is that they cause excess flexing of the tyre wall, which heats up the tyre too much. That's not going to be a problem in snow!

[filip00]

winter tires, - 2.3BAR for me. summer - 2.5bar.

[attack eagle]

theres a differnce between snow and slush. In slush you want a narrow contact patch to avoid hydroplaning.

[Ross]

Lower is better for snow. Pressure needs to be restored to normal for highway speeds to avoid overheating the tires.

[filip00]

snow tires should be as thin as possible to penetrate snow as deep as possible.

[bsell]

Will give you a larger contact patch with the ground but realize that you will not have handling as before. I watched a show about two guys driving across the Antarctic and their tire pressure was never over 2-5 psi!

Lowering the tire pressure from 'standard' pressure causes the weight to transfer to the outer edges of the tires, creating a 'cavity' in the middle which allows the tire to 'climb' on top of the snow. This climbing action keeps the tires from burrowing in and stopping the car in deep snow. Surf fishermen use the same technique when driving on the soft sand of the beachs.

As someone else said, running tires 'soft' creates heat within the tire due to excess flexing of the sidewalls and tread surface. I doubt running the tires under 28psi will make that much difference in driveability in the snow. So I am not a fan of reccommending really low pressures.

With all of that said, there is something to be said for 'digging' through the snow pack and getting down to the pavement. If the snow isn't too deep, a normal or slightly high pressure moves the weight to the middle of the tire. This creates more of a 'knife' effect, allowing the tire to cut through the slop and grab the street.

For snow tires on a car without LSD and a forward weight bias, I like narrower tires to cut through the snow.

Brian

[Claude]

Got another 6" overnite & still snowing. Wife took the truck, had to put a spare set of Blizzaks on mine this morning. Do I run them higher or lower than regular tires?

Thanks

My experience with many years in the snow (living east Quebec / Canada) is that you must stick to the car manufacturer recommanded pressure and it's the same in winter and summer. Otherwise you will modify the road handling of the car and certainly accelerate tire worning. The type of rubber and foot treading of the snow tires make the difference we need to get better performance in the snow and on the ice.