A while back I read somewhere if you experience sore knees from riding that you need to adjust the seat height. At least I believe I read it somewhere. So I am wondering if the seat might be too low or too high. I have not been putting much mileage on my bike, just in and around the small town that I live in, but yesterday I rode for about 8 to 10 miles (sorry I don't know the conversion to metrics) and my knees were getting sore. It was kind of cold out (about 24 degrees with the wind chill ~ sorry again about metrics). I rested on a bench for about 10 mins and drank some water. After that I was fine the rest of the way back home which was about 2 more miles.