I would agree that they shouldn't be loose exactly, but nor should be too snug. It's neither healthy nor comfortable to wear overly tight shoes. For that reason, I'm willing to loose a little bit of power. Not only will your feet become very painful when they swell after a long, hot ride, you'll also have a heck of a time during winter rides when you definitely don't want to cut off circulation with an overly tight shoe. I wear 7 1/2 in street shoes, and I think my SIDIs are size 40. Even with that, I think they feel a little snug in the toe box. I'd like to try Carnacs the next time around (if the SIDIs ever give out that is) because of that.