D'oh rode in the wrong gears

Spent 60 minutes tonight riding between a 52x17 and a 52x15 thinking I haven't done this combo before but the ride was too easy and I had a sinking feeling like I probably have been pedaling this combo since last week. Which after reading my blog was indeed the truth. I'll make it up tomorrow when I ride for 60 minutes in a 52x15 and 52x13 combo. Gotta get ready for Sunday's death climb.