[cucumber3732842]

>Snow tires can actually double your coefficient of friction on snowy pavement!

Citation? Seems to good to be true. Maybe studded tires on the perfect ice.

>The coefficient of friction drops fast on snowy ground,

NickCageYouDontSay.jpg

[vablings]

https://www.edmunds.com/car-reviews/features/tire-test-all-s...

It's likely more than double as the test results indicates lateral G not coefficient of friction. Snow tires make a bigger difference than any other factor. Good tires make a bigger difference on track too, more than any one single performance upgrade

[cucumber3732842]

That's vs the summer tires. Compared to the all seasons the results are much more modest and square with observed reality rather than internet hype.

From the link:

>Snow Test Results >No one expects the snow tires to come in anywhere but 1st place >on this wintry surface at AET. The point here is to see how big their advantage really is over all-season and summer tires.

>It takes 11.7 seconds for our Civic Si to accelerate to 40 mph on snow tires, and 14.5 seconds to get there on all-season rubber — nearly 3 seconds and 24 percent slower. As for the summer tires, well, they require, ahem, 41.7 seconds as they struggle to 40 mph. That's no typo; it takes a half-minute longer — 257 percent more time — for the summer tires to reach this modest speed.

>What about our traditional 0-60-mph test? Well, snow tires get to 60 mph in 19.1 seconds, while the all-season treads arrive in 22.9 seconds, nearly 4 seconds later. Forget the summer tires, however. The available 3,650 feet of snow — seven-tenths of a mile — isn't enough. We figure 67 seconds and 3,100 feet are needed to get there, and then there's the small matter of needing to stop again.

>And that brings us to our next test: full stops with ABS engaged. Here again the snow tires dominate, stopping from 40 mph in 156 feet, some 28 feet shorter than the all-season tires' 184-foot performance. Meanwhile, our summer tires skate to an ultimate distance of 351 feet, the ABS actuator rattling for all it's worth the whole way.

>Increase the starting speed to 60 mph and these distances more than double. It takes 362 feet for the snow tires to stop and 421 feet for the all-season donuts. The summer tires sit this one out because they can't manage to get themselves to 60 mph in the first place. (We do the math instead and come up with an estimate north of 800 feet.)

>Skid pad results follow the same now-predictable pattern. Our snow tires pull 0.30 lateral g, the all-seasons manage 0.28g and the summer tires produce a pitiful 0.15g despite a heroic effort by our shivering hot shoe.

[saalweachter]

I would note the big difference in that trial is for summer vs snow, with all-season showing smaller degradation.

So there's two things going on: first, snow tires are a softer rubber that functions better at lower temperatures. There is a zone of "warm" snowy weather where all seasons are just fine, but then you get below 20F or 15F or so, and the all season start to harden, and their performance drops off a cliff.

Second, snow tires are made to get packed with snow at low speeds, because the friction of snow on snow is higher than snow on rubber.

So damn cold weather or enough snow for the packing to kick in, and two snow tires will start beating four all season.