Recommended PSI for 18" Aero Winter Package?

[Birdman325]

I have seen some conflicting reports about the recommended PSI for the Pirelli Winter Sottozero II tires that come as part of the Aero winter package.

My car was delivered with the 19" tires, so I have assumed (incorrectly?) that the door jamb label is specific to the 19".

When the 18" winters were installed, the PSI was set to about 47 - 48 all around.

Thoughts?

 

[gilscales]

42 psi has been the recommended tire pressure now for a while whether 18's or 19's

 

[Birdman325]

Thx. Wasn't sure if there were differences specific to the 18" winters.

 

[MountainPass]

42psi for comfort, 45psi for range/handling. Those few psi are surprisingly noticeable.

 

[burnside]

Just to confirm, is that 42psi before any driving?

 

[Birdman325]

Haven't dropped down to anything under 45 and personally, I am fine with the comfort and ride quality. Still find the road / tire noise on the highway to be higher than other cars, but that just seems to be what it is.

 

[ConcordeSST]

42psi for comfort, 45psi for range/handling. Those few psi are surprisingly noticeable.

Wouldn't higher PSI reduce traction in snow due to less contact between the tire and the road?

 

[lgkahn]

I keep mine at 41 in the garage at 34-40 decreases.

 

[mswlogo]

Just to confirm, is that 42psi before any driving?

Pressures are ALWAYS cold pressure.

Yes.

 

[CCIE]

Wouldn't higher PSI reduce traction in snow due to less contact between the tire and the road?

No, higher pressure is usually better in winter/snow. A narrower tire would also be better, but isn’t really an option for us.

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=168

 

[burnside]

Pressures are ALWAYS cold pressure.

Thanks!

 

[mswlogo]

No, higher pressure is usually better in winter/snow. A narrower tire would also be better, but isn’t really an option for us.

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=168

I don’t think you can compare a narrow tire to a wider tire that’s over inflated.

The old rule of thumb is to typically run snow tires a couple pounds less.

Also narrow tires might dig down better in some instances but a wide tire will grip ice better which is probably the most dangerous thing a car/driver is faced with in winter. Not getting through a foot of snow.

Also the biggest problem with deep snow isn’t the best tread or width. It’s clearance.

That article is interesting. I don’t buy the logic of compensating softer handling with tire pressure. The tire is what it is and you may be defeating it’s performance in snow, when you bought the tire for snow !!!

Not sure about the whole temperature radiation thing. I do wish manufacturers would disclose what the target pressure they are shooting for rather than compensate for us. Because what we expose the car to varies a lot. Like one might be a city car that never warms the tire up much. Another person might have a 100 mile commute doing 80 mph. The target temp (and pressure) would be hugely different, yet they both get the same cold pressure spec.

I know, the car should calculate what cold pressure you should put based on its learning !!!

 

[Atari2600]

I don’t think you can compare a narrow tire to a wider tire that’s over inflated.

The old rule of thumb is to typically run snow tires a couple pounds less.

Also narrow tires might dig down better in some stances but a wide tire will grip ice better which is probably the most dangerous thing a car/driver faced in winter. Not getting through a foot of snow.

Also the biggest problem with deep snow isn’t the best tread or width. It’s clearance.

How about run at 50 PSI then when it snows run at 40 PSI? Letting air out of tires is really easy. I'm running my Nokian R3 at 45 PSI and thinking of increasing them even higher. I ran my MXM at 45 and Nokian instructions say to run winters higher than your all-season/summer tires.

Tire Inflation Tips / Nokian Tires

For winter tires, you should inflate the tires to 3 PSI above the summer tire recommendation, since tire pressure decreases as much as 1 PSI with each 10-degree drop in temperature. The temperature in a warm garage can be up to 60˚F higher than outside. If the tire pressure is measured inside, it will be too low for outside temperatures.

Example: The temperature in the garage is 68 ˚F, while the outside temperature is 15˚ F. If the pressure is adjusted in the garage, the pressure added to the tires must be 3 PSI higher than the recommended value to ensure a correct pressure level outside.
​

Driving tips and tire care in winter | Pirelli

For winter tires, a rise in pressure of 0.2 bar is recommended due to thermal fluctuation that leads to a decrease in tire pressure. It is preferable to measure pressure in cold conditions at least 30 minutes after using the vehicle, in order to be sure that the heat produced while driving has not modified the pressure. The winter tires check has to be performed not only after traumas (such as bumping the tires), but at least once a month.​

 

[StealthP3D]

I have seen some conflicting reports about the recommended PSI for the Pirelli Winter Sottozero II tires that come as part of the Aero winter package.

My car was delivered with the 19" tires, so I have assumed (incorrectly?) that the door jamb label is specific to the 19".

When the 18" winters were installed, the PSI was set to about 47 - 48 all around.

Thoughts?

When the winter snow started falling I experimented with pressures of the 18" Pirelli Sottozero's and settled on 46-47 PSI stone cold. They work really well on snow/ice at these pressures and, that's also the best dry pavement pressure as well (for maximum performance). After a good drive your TPMS will read 50-51 psi. But pay attention to the following disclaimer:

If you have been running them at 42 PSI or, God forbid, even lower, it will take up to 1,000 miles of driving for the tread to wear into the shape of the road after raising the pressures and, during this period you will have even less snow/ice performance than at the lower pressures. So don't give up on the higher pressures before the treadwear has settled into the new pressure. This phenomenon is not unique to the Sottozeros, I've seen it on every winter tire I've had in the last decade or more.

The tires do really well when properly inflated but you might feel they lack drive when accelerating, particularly if they have been accelerated briskly numerous times on bare or bare/wet pavement because this wears the biting edges of the tread blocks into an unfavorable shape for traction in snow and ice. And who doesn't accelerate briskly in a Model 3? A normal acceleration in a Model 3 is a brisk acceleration!