According to DaddyMonkey :
ya gotta be kidding us, right?

Heh. I just replaced a tire on a trailer, my first experience.
Never again...

[I had little choice, since the wheel bolts were rust-frozen _solid_ and
I couldn't get the wheel off. The trailer was out in the boonies.]

Installation is about the same as removal. Two people, two pry-bars, big
hammer... BUT WAIT!... you're going to need some rubber lubricate...
liquid soap will work just fine.

Wish I had thought of that. Fortunately, I didn't wreck the tire.

Assuming you now have your new tires installed on the rims, without
totally destroying them, how are you going to inflate them?
I have seen rock-crawlers and artic guys inflate tires by spraying
starter-fluid inbetween the bead and rim, and then "flicking-there-Bic"
--BOOM!--
(I didn't say this .... Don't try this at home kids, but a man's gotta
do what a man's gotta do, I guess).
Do you see where I'm going with this?
NO? --- okay

This works and is relatively easy: Take a chunk of rope, and wrap it a turn
or two around the circumference of the tire and tie it off. Then, using
a heavy screwdriver or a chunk of wood, do a "spanish windlass" to
tighten the loop. This expands the tire against the bead.

It helps to have something that will dump air into the tire _fast_. Ie:
an inflater tank.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.