There was a special narrow pry bar with a hook-shaped end that's used to pry the wheel halves apart, but you'd need to find a commercial tire shop that's been in operation 30-something years to have much likelihood of finding one. A BIG flat-bladed screwdriver and some colorful language works, sometimes. Once the wheels are apart, please use a cutting torch or a big sledgehammer on the pieces to assure nobody gets tempted to reassemble them.
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!