Thanks for starting this thread Marty97....I have a road trip coming up and just checked the spare. It was down to 36psi
but back up to 60psi now thanks to this discussion.
I've only had to use it once but it saved my @sh in the middle of nowhere. Driver's front hit something and took out the sidewall, fix-a-flat wouldn't have helped.
Since then it's comforting to know I have options.