Have you checked the mount of your spare tire lately??
There are a lot of members on here who remind us of the battles we must fight when it comes to rust on our vehicles. A local incident happened on Sunday where the mount of a spare tire became so rusted that the tire was dropped from its mounting position on a pickup truck. The tire bounced down the road and landed on someone's windshield then preceded to get lodged into the wheel well of the next car. The amount of damage was surprising considering it was just a tire that came loose, but the owners of the damaged cars seem more concerned with the scenario of "what could have happened". Luckily no one was injured but this is definitely worth consideration for many people whose vehicles are subject to corrosives such as the winter month's road salt
here is a 2 1/2 minute video if you're interested