Commuting around OP's weight, I'll normally pump tires up to 90 psi (used to go to 100, but I don't need that). Ride until they feel a bit soft, which is about 70 psi on my thumb, and pump it back up. I could go as low as 75 with good comfort and adequate speed, but I don't pump every day (just every 2nd or 3rd day). 70 psi is a drag, it's a good way to get extra exercise without extra speed IME.