Which Snows and Why Poll?

[StealthP3D]

I'd like to add that on dry roads and wet roads, the Sottozeros are dramatically better than the X-Ice. I actually think the Sottozeros stop and handle better in dry and wet conditions than the stock Michelin Primacy MXM4s.

I agree and that's exactly why I like the Sottozero's so much! They are more than adequate on treacherous snow and ice surfaces yet they totally excel in terms of sporty driving on bare pavement, especially if it's cold and wet. Steering response is crisp and precise, even for a non-winter tire and the ride is quiet and civilized.

Also, I found that 39 PSI works best with the Sottozeros on my car and I like 42 PSI on the stock MXM4s. I don't know if it's the difference in size or tire construction, but 39 just seems to have the best handling and ride balance.

Are using the built-in TPMS to judge pressures or an accurate stand-alone tire gauge? The built-in system is consistent and fairly accurate (at least on our two Model 3's) with the exception that they read lower pressure than actual at altitudes above sea-level. This is because the actual tire pressure is the difference between atmospheric pressure and the pressure inside the tire but the TPMS has no way to compare the pressure to the atmospheric pressure so they simply use a fixed standard value. That's why the TPMS reads low at higher altitudes.

I'm thinking you might live at altitude and thus are running pressures a bit higher than you are reporting. I arrive at my preferred pressures by driving the car hundreds of miles under various conditions and paying particular attention to how "glued to the road" it feels when cornering near the limits of traction. At pressures below 44 psi cold I find the Sottozero 2s cannot handle as many corner G's without starting to release early. The optimum pressure will be slightly lower with a completely empty car (I do my testing with about 400 lbs. of people and luggage). The pressure for optimum straight line stopping distance and acceleration is likely slightly lower than for optimum corner grip. In warmer weather the optimum pressure is also lower because the tire builds more heat (and thus natural temperature induced pressure rise) than in cold weather.

Little known fact: When testing for optimum pressures it is necessary to let the tread wear to the new pressure before drawing conclusions. This is because the tread wears into whatever pressure you are running at. Whenever the pressure has been adjusted up or down more than a pound or two, the traction will be less for a couple hundred miles (until the tread wears into the new pressure).

 

[GregD60]

Are using the built-in TPMS to judge pressures or an accurate stand-alone tire gauge? The built-in system is consistent and fairly accurate (at least on our two Model 3's) with the exception that they read lower pressure than actual at altitudes above sea-level. This is because the actual tire pressure is the difference between atmospheric pressure and the pressure inside the tire but the TPMS has no way to compare the pressure to the atmospheric pressure so they simply use a fixed standard value. That's why the TPMS reads low at higher altitudes.

I'm thinking you might live at altitude and thus are running pressures a bit higher than you are reporting. I arrive at my preferred pressures by driving the car hundreds of miles under various conditions and paying particular attention to how "glued to the road" it feels when cornering near the limits of traction. At pressures below 44 psi cold I find the Sottozero 2s cannot handle as many corner G's without starting to release early. The optimum pressure will be slightly lower with a completely empty car (I do my testing with about 400 lbs. of people and luggage). The pressure for optimum straight line stopping distance and acceleration is likely slightly lower than for optimum corner grip. In warmer weather the optimum pressure is also lower because the tire builds more heat (and thus natural temperature induced pressure rise) than in cold weather.

Little known fact: When testing for optimum pressures it is necessary to let the tread wear to the new pressure before drawing conclusions. This is because the tread wears into whatever pressure you are running at. Whenever the pressure has been adjusted up or down more than a pound or two, the traction will be less for a couple hundred miles (until the tread wears into the new pressure).

I use "an accurate stand-alone tire gauge". I do live at altitude, and the TPMS consistently shows 3 to 4 pounds lower than the pressure gauge. I measure the pressures when the tire is cold in the morning before driving for consistent results. After driving for a little bit, it is typical for the pressures to go up about 3 PSI according to the TPMS.

From a performance standpoint, I tend to prefer using the old chalk method since I don't have a tire pyrometer, but I've never bothered doing either type of test with winter tires. That's something that I save for the track. For the street, I experiment over time until the car has the best combination of ride and handling feel to me. I'm really not looking for every last tenth of a second on the street.

As for your finding of 44 PSI to be your preferred pressures versus my preference of 39 PSI, that could obviously be due to a number of factors. The biggest factor I think is that it seems that you're looking for a maximum performance handling setting while I am looking for a blend of ride and handling. Also, Sottozero 2s could simply require different pressures from Sottozero 3s. One other thing that I've noticed is that in snow and ice, particularly slushy, conditions, the traction is better with the lower pressure while giving up little to nothing in dry conditions.

 

[StealthP3D]

I use "an accurate stand-alone tire gauge". I do live at altitude, and the TPMS consistently shows 3 to 4 pounds lower than the pressure gauge. I measure the pressures when the tire is cold in the morning before driving for consistent results. After driving for a little bit, it is typical for the pressures to go up about 3 PSI according to the TPMS.

From a performance standpoint, I tend to prefer using the old chalk method since I don't have a tire pyrometer, but I've never bothered doing either type of test with winter tires. That's something that I save for the track. For the street, I experiment over time until the car has the best combination of ride and handling feel to me. I'm really not looking for every last tenth of a second on the street.

As for your finding of 44 PSI to be your preferred pressures versus my preference of 39 PSI, that could obviously be due to a number of factors. The biggest factor I think is that it seems that you're looking for a maximum performance handling setting while I am looking for a blend of ride and handling. Also, Sottozero 2s could simply require different pressures from Sottozero 3s. One other thing that I've noticed is that in snow and ice, particularly slushy, conditions, the traction is better with the lower pressure while giving up little to nothing in dry conditions.

Oh, I just remembered one likely difference. Tesla was sold out of the Sottozero's when I bought mine and so I'm running the same size and speed rating but one notch lower load rating. They probably prefer more pressure due to having more supple sidewalls.

 

[Snow Drift]

Bubbling this thread up to the top as winter seems to be fast approaching. Any new 2020 winter tire options for Model 3? I'm currently debating between Sottozeros and X-ICE.

The X-ICE Xi3 were replaced by the more aggressive X-ICE SNOW. I ordered them, haven't arrived yet.

Here is TR's review:
https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=258

This review liked them.

 

[StealthP3D]

The X-ICE Xi3 were replaced by the more aggressive X-ICE SNOW. I ordered them, haven't arrived yet.

Here is TR's review:
https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=258

This review liked them.

I'm not a fan of any winter tire review that only judges the tires relative to the best grip on snow and ice. Because very few winter tire buyers live in an area that doesn't have predominately bare pavement on the most used driving routes. And if that's the case then things like noise and vibration, emergency stopping/swerving on cold bare pavement and tread wear patterns and driving enjoyment will play a big part of most peoples tire selection.

It's easy to make a winter tire that will out-grip the rest on snow and ice but fail miserably at the other tasks that winter tires routinely need to do. I no longer buy the winter tires with the best snow/ice grip because the other compromises are simply too great. A winter tire with middle of the pack performance on snow and ice doesn't make me nervous because when the roads are really nasty there is always one yahoo making sure everyone behind them has to creep along at 35 mph. I'm more concerned about how they perform when traffic is moving at high speeds on bare or bare/wet pavement. And that's why I like the Sottozero tires by Pirelli so much. They are a well-rounded winter tire, not a one-trick pony that I can't wait to take off before I should when spring rolls around.

 

[Snow Drift]

@StealthP3D

In the past I've used Dunlop SP Winter Sport M3 (WRX), Michelin Pilot PA3 (WRX), Blizzak WS80 (Crosstrek) and Michelin X-ICE Xi3 (STI and Model 3). I found the X-ICE to perform well in dry/wet/snow. The Dunlop SP WS M3 and Michelin Pilot PA3 were performance snows and I enjoyed that very much in the dry.

I guess you haven't had the sidewall issues with Sottozero? They also never rate as high as the other Performance snows on TR.

 

[GregD60]

@StealthP3D

In the past I've used Dunlop SP Winter Sport M3 (WRX), Michelin Pilot PA3 (WRX), Blizzak WS80 (Crosstrek) and Michelin X-ICE Xi3 (STI and Model 3). I found the X-ICE to perform well in dry/wet/snow. The Dunlop SP WS M3 and Michelin Pilot PA3 were performance snows and I enjoyed that very much in the dry.

I guess you haven't had the sidewall issues with Sottozero? They also never rate as high as the other Performance snows on TR.

I've had Sottozero 3s on my Model 3 and on a BMW 3 series and they've been excellent tires in my experience. The one negative is that they wear out quickly, 3 winter seasons or about 15k miles and they're down to about 4/32" of tread. I've also had Blizzaks and X-Ice on other cars. The Blizzaks have the best traction of any of the winter tires I've tried for the first half of their tread, a little bit better than the X-Ice, but after that, their traction on snow and ice is more like the Sottozero 3s. The Blizzaks are also noisy. The X-Ice have almost as good of traction as the Blizzaks but they maintain most of their traction throughout their tread life, and their tread life is also the longest by a substantial margin of the winter tires I've used.

The Sottozero 3s have much better dry and wet weather traction, and dramatically better steering response than the Blizzaks or X-Ice tires. Around here, the roads are much more often dry or wet rather than covered in ice or snow, so I find the Sottozeros to be a better choice. For the bad days, they're only a notch behind the grip of the Blizzaks or X-Ices, and I've found them to be quite capable. I haven't had any sidewall issues with the Sottozeros, nor have I heard of an issue with them.

 

[MatildaModelY]

couple questions for the group - what is the optimal 19" tire size for winter tires?

And any real world take on the Xice 3's vs the Alpin PA4?