Ok first off, I have no idea whose knees these are, but thanks for letting me borrow them for the picture

Moving on.... I had a long ride over the weekend. Two 85mi days. Both days, right as I approached the 65-70mi mark, my knees began to bother me. The pain is on the lower, front to inner sides of both knees. Anyone think they may know the fitting problem? Or is that just when I began to tire, and have some kind of breakdown in form? (like a L/R foot angle) Can it really be a fit problem if I can ride 1x 10mi, 3x 20-26mi, and 1x 40-50mi sessions each week w/o a problem, but once I surpass 60+ in a single session, it starts? I even had a long break before this past weekends ride thanks to the rainy weather...so it wasnt a result of too much riding.
Any help/thoughts narrowing down a specific place to look or adjust is appreciated