They're smooth and don't have any grippy tread, but I love my Armadillos. They are skinny tires, but they are bombproof. I've had them on the bike a year and a half and haven't had a flat yet (and I get flats fairly often on my other skinny road bike tires). And trust me, I ride through all kinds of stuff. The gravely stuff on the shoulder, the salt grime stuff in the winter, and even on gravel roads. I think I paid $25-30 each.