Tug like the dickens...
I replaced my tires last year, and definitely requires wheels being removed to do this.
From what I've read, most tires are held on by friction and fit, no glue, so the fit is VERY tight.
I had to do exactly what was said with using some screwdrivers to help pry them on, even after soaking in hot water.
One trick that may help, and that I did, involved using the 'trigger-style' clamps that have padded jaws. There's a tendency for the tire to slip off as you're pulling it around, and adding a few of the clamps to hold the tire in place around the wheel will help you get it on, without subsequently slipping off adjacent areas first.
Just be careful...easy to pinch yourself putting these tires on.
One more thing...if the outer rim of your wheel has raised lips, be sure the tire stays in between these. I had to push my tire around a little to help get in between these lips.