Do not deflate a tire on a multi-piece wheel unless you're planning to dismantle it, and NEVER try to add air to one that's flat or seriously low without a breakdown and reassembly. It's OK to remove and reinstall fully-inflated split rims. The internal air pressure makes it impossible for the pieces to separate. The danger is of parts coming unglued while doing the initial inflation after a tire change or a flat repair. Always use a cage, or wrap a heavy chain through the wheel in several locations when inflating. I use a clip-on air chuck and a ball valve in a 20-foot-long air hose extension and hide behind something substantial.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!