This was posted in the sticky about making your own studded tires a few years ago. You can leave the studs off the middle of the tires and just have them at the edges. Then you can ride on dry pavement without the studs coming into contact with it. If you do need the studs, just let a little air out of the tires.

I don't use studs myself, but thought that's the way I'm going to try first if I do want to use them.