Winter tire pressure and ice- higher, lower, same?

[geeman789]

We had a nasty bout of freezing rain, followed by temps dropping to 0*f , and the roads are a mess. Sheet ice everywhere, and it's too cold for salt to do much.

Would airing down the tires somewhat make much difference in traction...? Or conversely, would pumping up the tires more decrease the contact patch and create more pressure, thus more grip... ? On ice, I'm thinking more surface area is better...

I am currently a couple of psi below the recommended 33 f / 32 r , running 31 / 29 for now. Seems to work slightly better... heat is not an issue at these temps, and the tires have adequate load capacity even at lower psi... I may try even lower to experiment, and later higher...

Or, is the difference in performance not enough to bother with at realistic tire pressures... I know the off-road guys will air down to 10 or 15 psi in sand etc., but I won't go that low obviously...

And, tire pressure is set cold, at outside temps... brrr. So no loss of psi as car moves from warm to cold.

Thoughts...?

 

[BobsArmory]

Guys that run in the sand want to float on top of the sand. Unless you are in the deep wilderness type snow, you want to get down to the pavement where the hard stuff is instead of floating on top. All I run here in Michigan is standard pressure but as always, your mileage may vary

 

[4wheeldog]

To some extent, lowering pressure will put more rubber in contact with the road. And when there is ice, tire temperature is somewhat less of an issue.

I would not go as low as one might when driving in sand, however. Maybe 4 to 6 pounds lower would be the limit. And only when driving under lower speed restrictions, maybe 40mph tops. I would not do it at all if I were to drive at highway speeds.

If it is that bad out, the best advise is to stay home. If slowing down is not enough, sitting by the fire is a useful alternative. Even if you drive perfectly safely, you are at the mercy of the less skilled.

 

[raytseng]

use standard tire pressure.
IF things are that bad for your tire choice, throw on chains or other traction device-or stay home

 

[Bluestream]

Wait a few hours till they sand the roads, Chains on ice is very dangerous,,,

 

[Ken2]

Lowering the pressure allows the tire to flex more, warm due to the flexing, and being warmer and softer rubber perhaps grip better. If you can make good day-to-day comparisons, let us know.

I'm disappointed in the ice grip of my Hankook Winter I*cept Evo tires. My previous Blizzaks were better. The I*cept Evos are good on dry, deep water, & snow.

 

[geeman789]

Originally Posted By: raytseng
use standard tire pressure.
IF things are that bad for your tire choice, throw on chains or other traction device-or stay home


I use a premium studless winter tire, the Toyo GSI-5... and they are excellent winter tires... AND I have AWD... i have no issues getting around.

The question is more one of this... by playing around with tire pressure, can one obtain a MEASURABLE improvement in pure ice traction... without using studs...? ( And chains would be useless... 1/4 inch of hard ice)

Any ice racers out there... running pure rubber class, ie no studs...?

 

[Warstud]

The Real Question Is:

Are you really going to inflate/deflate your tires every time it snows or the roads are icey? Not me.

 

[Rand]

I usually run door placard pressure to +4psi

 

[geeman789]

Originally Posted By: Warstud
The Real Question Is:

Are you really going to inflate/deflate your tires every time it snows or the roads are icey? Not me.


Compressor in the garage... takes about 2 minutes to air up again...! I adjust for temp all the time... not unusual for our temps to move 30*C from week to week... last week we hit -29*c ( -20*f) , next week forecast highs of + 5 *c ( +41*f)

 

[eljefino]

Winter tires often have softer sidewalls so the tread blocks can throw snow out.

IDK about ice though. When it gets down to zero you lose three pounds anyway compared to freezing temp.

I don't like messing with my pressure all that much during extreme weather as there's the off chance of getting condensation in the tire valve and having it cause a leak.

I agree on the "stay home". As a driver you get feedback from the car and tires about their handling and limits, if you start playing with pressure on a day-to-day basis your muscle memory won't cope with sudden issues.

 

[SwampSurvivor]

I drop my winterfarce tires to the recommended 32PSI in slippery conditions. 32 is the recommended pressure by Ford - there is a definite improvement of traction in snowy conditions.

The problem is, at 32, they will wear more on the outside so I have to run them at higher pressures when it is not snowing or icy.

 

[CapriRacer]

Some thoughts:

First, pavement has much higher friction than snow - and higher inflation pressure helps get the tire through the snow and in contact with the pavement.

Second, inflation pressure follows temperature - for passenger car tires, about 1 psi for every 10°F. I think a good strategy is, at the beginning of the winter driving season, to overfill the tires by 5 psi when the temp is about 50°F with the idea that when the temperature drops to 0°F, it will be at the specified number. (Adjust this according to local conditions.)

Third, drive according to the conditions. When it is zero, drive more cautiously. Not only does friction decrease with temperature, but ice can form in the oddest places.

Oh and ice can form as high as 37°F. I can't remember exactly how that happens (it's been a while since I looked that up), so don't think just because you can see unfrozen water that there isn't any ice.

 

[ottomatic]

Originally Posted By: CapriRacer
Some thoughts:


Oh and ice can form as high as 37°F. I can't remember exactly how that happens (it's been a while since I looked that up), so don't think just because you can see unfrozen water that there isn't any ice.


I just had to google it> http://www.atmos.washington.edu/cliff/Roadway2.htm