How to decide when to go back to summer tires?

[StingertimeNC]

I've been at multiple track events where the first session of the day started with temps around 25-30℉ with no issue warming the tires after a few laps. Several cars also running 100 or 200 TW tires in the same weather. That being said, I would probably want all season tires if I constantly drove around under 25°. In central NC, we have some low temps in the morning, but almost always get above 30 during the day. I just take it easy when it's cold and no issues at all.

 

[Fred 930]

from the manual:
Cold Weather Driving Summer Only tires and Ultra High Performance (UHP) tires are very sensitive to ambient temperatures and are designed to be used at temperatures above 45°F (7°C). If the vehicle is operated with Summer Only tires or UHP tires at temperatures below 45°F (7°C), the tires will provide decreasing amounts of grip and other performance attributes. If the vehicle is operated with Summer Only tires or UHP tires at temperatures below 14°F (–10°C), the tire tread may lose their elasticity and become brittle, resulting in permanent damage to the tread. A damaged tire may fail during use. Therefore, if you operate the vehicle when ambient temperatures are below 45°F (7°C), we recommend that you install other tires (e.g., mud+snow, winter) that are designed to provide appropriate performance attributes under the anticipated conditions.

Thanks - very interesting information on operating with UHP Summer tires. But I still wonder if damage will result from storing the tires (on the vehicle, or not) at below 0°F or colder? I've had track tires that must be kept warmer / prevented from freezing (over winter) - so they can't be stored in my garage.

 

[SilverRocket]

Thanks - very interesting information on operating with UHP Summer tires. But I still wonder if damage will result from storing the tires (on the vehicle, or not) at below 0°F or colder? I've had track tires that must be kept warmer / prevented from freezing (over winter) - so they can't be stored in my garage.

For the PS4S' Michelin warns:

Note: Tires exposed to temperatures of 20 degrees F (-7 degrees C) or lower must be permitted to gradually return to temperatures of at least 40 degrees F (5 degrees C) for at least 24 hours before they are flexed in any manner, such as by adjusting inflation pressures, mounting them on wheels or using them to support, roll or drive a vehicle.
Flexing of the specialized rubber compounds used in Max Performance Summer tires during cold-weather use can result in irreversible compound cracking. Compound cracking is not a warrantable condition because it occurs as the result of improper use or storage, tires exhibiting compound cracking must be replaced.

So basically if you're storing your car outside and it's below 20F/-7C overnight, your tires are suffering. This is where I get my rule from, that if the car will be started below 32/0, best not change them although I do think for the chiller mornings, I think a garage kept car should be fine since it's leaving from greater than 40/5 degree weather and should stay warm-ish while driving even if the temps outside are around freezing.

 

[Needs3Pedals]

Thanks - very interesting information on operating with UHP Summer tires. But I still wonder if damage will result from storing the tires (on the vehicle, or not) at below 0°F or colder? I've had track tires that must be kept warmer / prevented from freezing (over winter) - so they can't be stored in my garage.

this was presented on a Mustang forum as if it had come from Michelin buti haven’t been able to find it on their website:

"Note: Tires exposed to temperatures of 20 degrees F (-7 degrees C) or lower must be permitted to gradually return to temperatures of at least 40 degrees F (5 degrees C) for at least 24 hours before they are flexed in any manner, such as by adjusting inflation pressures, mounting them on wheels or using them to support, roll or drive a vehicle.

Flexing of the specialized rubber compounds used in Max Performance Summer tires during cold-weather use can result in irreversible compound cracking. Compound cracking is not a warrantable condition because it occurs as the result of improper use or storage, tires exhibiting compound cracking must be replaced".

I have access to a differential scanning calorimeter (DSC) at work and I’m tempted to do a little test on our tires to check for glass transition (Tg’) temperature(s). I’m in Georgia and have kept the stock tires on but I just drive an old accord when it’s below 35F or so.

 

[optronix]

This is probably in the owner's manual, but I've not yet taken delivery of my car.

What is the minimum storage temperature of the "summer" tires used on the Type S?
Must they be kept above freezing (which is a common requirement for many track tires)?

I'm assuming (for liability reasons) they will tolerate near zero storage temperatures in unheated garages?

Also I think it matters if they'll be mounted on the car or not on the car. I don't think you'll have a problem if you're not driving on them and they stay above freezing, in either case. If the temps drop below freezing, probably not an issue if they're not on the car; if they are then it could possibly lead to flat spots.

Also if they're not on the car don't stack them, that's bad. Leave them vertical if possible.

I've been at multiple track events where the first session of the day started with temps around 25-30℉ with no issue warming the tires after a few laps. Several cars also running 100 or 200 TW tires in the same weather. That being said, I would probably want all season tires if I constantly drove around under 25°. In central NC, we have some low temps in the morning, but almost always get above 30 during the day. I just take it easy when it's cold and no issues at all.

I know people do this all the time, but I've never been comfortable with it. Not so much from a damage-the-tires perspective, but I don't like the sensation of driving on hockey pucks.

I would probably alter my comfort zone if I lived further south. Here in Maryland it gets and stays cold enough to justify all seasons. Especially if it's cold and wet. I learned my lesson.

 

[creaturemachine]

Also if they're not on the car don't stack them, that's bad. Leave them vertical if possible.

*glances over at my stacked tires* Welp, I guess these are going in the trash.

 

[optronix]

*glances over at my stacked tires* Welp, I guess these are going in the trash.

Should have added, if they're mounted on a wheel you're probably fine.

 

[bpebler]

That’s all good to know. My oem tires and wheels are stacked (not separated) on a rolling cart in the shop. We typically plug in an electric heater when it gets really cold though which helps stay around 40° ish.