The PS4S was the first tire I saw with all kinds of warnings about temperatures below something like 5C. They said if it was below something like -10C you weren't permitted to do anything, even check tire pressure, or the sides might split.
Before buying PS4S I inquired in a couple of places about whether this was a dramatically different tire, or just dramatically increased warnings. In the fall and spring occasionally I operate my summer tires near freezing and wanted to know if these things would rupture like the warnings seem to say. (e.g. a cold front blew through, it's 6am and 36F, going to be 60F later, and I need to drive 1.5 miles in the dry to my train station. Going to be 80F next week - I'm not putting my winter tires on)
There was mention of something with a particular car that came with PS4S, like the Z06 or something, being made in MI and shipped in sub-zero cold snap. The sides of the tires split wide open in great numbers and Michelin didn't want to be held responsible. So, now there are dire warnings of consequences.
You should be fine if they are stored in outside conditions but not touched at all. Better would be find an indoor spot for them. I think the warnings even say that if they experience below -10C they must acclimate for 24 hours to warmer temperature before doing anything. I'll see if I can find the actual warning....
Here's the text from a US Michelin site:
Quote:
he Pilot Sport 4S excels in warm dry and wet conditions, so like all Max Performance Summer tires, is not intended to be serviced, stored nor driven in near- and below-freezing temperatures, through snow or on ice.
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.
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Interestingly, here's the text from the Michelin CANADA site, which is what I've seen for UHP tires for decades:
Quote:
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Summer tires are primarily designed for high-performance vehicles and provide optimal dry and wet performance levels in a temperate environment. Summer tires are not designed to be used during the winter season where temperatures are colder and approach freezing consistently as their performance would be less than optimal.
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Here's the C7 Z06 article:
https://gmauthority.com/blog/2015/03...cracked-tires/