Last 2 rides ive done ive been getting knee pain from around 20 miles in, last week i finished the 40 miles i had planned but couldn't walk all weekend. Currently im at the side of the rd 30 miles in waiting for the mrs to pick me up. Another weekend not being able to walk! It starts gradually and gets worse over time, seems to be more then spinning up hill, not so bad standing up. It starts like a cramping feeling at the top of my calf, back of my knee. Any ideas?