I didn't have a problem with the rear Avon Viper Stryke. It slipped on almost too easily. I didn't even have to use a tire iron to get the second half of the tire over the rim, just pushed down on it with my hands.
The front tire, though... you'd swear it was actually a 12" tire trying to be fit on a 13" rim. Had to use a high-volume air compressor to fill the tire because the bead wouldn't seat and the Costco air compressor wouldn't blow enough air.
I had to fill the tire to 60 PSI, and even then, only one side of the tire popped out and seated the bead, the other side just sat there not moving. It had soapy water on the tire and rim, too. It only seated after I got angry and gave the tire a swift kick. Then I lowered it to 40 PSI and took it home to balance it.
I think for the next set of tires, I'll go with the Michelin Power Pure SC tires. It's a dual compound tire, so it's grippy in the twisties, and long-wearing in the straights.