I'm looking at putting summer tires on my 89, I don't drive this car at all below about 50 deg but it is stored in sub-freezing and even sub-zero temps over the winter. Would it be ok to store the car on jackstands with the summer tires on and covered (similar to an RV)? I don't have a second set of tires and don't have access to a heated garage. I've heard mixed opinions that summer tires should not even be exposed to sub-freezing temps, and others that just say don't DRIVE on them.