These are 38mm tires. I had a pair of the Compass version, but one developed a bulge in the casing. I was surprised, since I hadn't hit anything to cause a failure. Until then, they certainly were fast and smooth over any kind of paving and on gravel. And the perfect tire for crushed stone rail trails, floating on top of the surface.

At 170 pounds, I ran 38 psi front and 45 psi rear. I don't think I ever had to inflate higher than this to seat them.