The key used for most of the locks on the PC is the most common key in the RV industry. I for one prefer the lock on my spare tire to be a little less common, like it is now. Having said that most locks are easily picked by any good thief.
I question putting to many heavy things in with the tire as that is the farthest place back from the axel. I prefer to put heavy items in the side compartment behind the batteries, in the middle of the coach.
This is just my way of doing things.