Probably could not apply enough pressure. Were the seats well soaked ? Liquid detergent works well. Needles removed. Old time trick that should work with a 19" was to inflate a well lubed bicycle tube between the rim and the tire. Tire would then inflate and pop the tube out.

And then there was the real old time trick that involved a little "flammable liquid" but is not recommended.

ps in the bad old daze we used a lot of tricks to inflate say a 10.45x15 on a 12" rim at the track where a big compressor was not available. Of course those sidewalls were so thin you could almost see through them. Still have my irons. BTW ever use a jack to separate the bead from a rim ? (tow car is best)