I had 700x60s a few years ago that I put on a mountain bike. They were much, much faster than the knobbies I had before, and in general they seemed fast. They rolled over cobblestones like they weren't even there. That doesn't happen with my Marathon Supreme 42s by a long shot. I ran as low as I could without squishy cornering and thought they were fast and comfy. It was lower psi than I expected. Like 40 or less. Not sure if that helps.