Reply With QuoteI'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.
Major Contributor
Snow tire pressure - higher or lower?
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
gale
92 735i 5-spd, turbo project finally underway!
Big Time Poster
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.
4 Grand Master
31 Front and 35 rear is what I do.
Big, Big Time Poster
Empirical advice follows that lower pressure would be better.
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!
Big, Big Time Poster
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!
Major Contributor
Grand Master
theres a differnce between snow and slush. In slush you want a narrow contact patch to avoid hydroplaning.
4 Grand Master
Lower is better for snow. Pressure needs to be restored to normal for highway speeds to avoid overheating the tires.
"The gas pedal wouldn't go to the floor if it weren't meant to be there"
Major Contributor
snow tires should be as thin as possible to penetrate snow as deep as possible.
Big, Big Time Poster
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.Originally Posted by Black 535i
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
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