Just some thoughts...
If you don't have one, you will need one.
The blowout will be in a bad place on a dark and stormy night.
The AAA, Good Sam, RV Club, Etc. company won't be able to locate the correct tire right away.
When they do find a tire it will be cheap, AND overpriced.
There are those who say it's never happened to me, so why bother... I guess that some make the same case for not wearing a seat-belt.
Please note, I would NEVER try to change my own motorhome tire, but that's just me.
This is what we use:
Roadmaster Inc. - Tow Bars, Braking Systems & RV Accessories
It's rock solid, lowers the tire to the ground, and allows you to pull a trailer or toad, carry bikes, etc.
Works for us, and the peace of mind is priceless.