Originally Posted by
Kind of Blued
Lets not. The title of your thread is "knee problem developing". Stop that development ASAP by getting a medically-based professional bike fit to figure out why your knee hurts. I'm only 25 and just went through this whole ordeal (chondromalacia) with my knees. Once you know you aren't going to damage your knees by riding hard, then you can work on riding those big gears at 90-100 RPM on flats to get stronger.
+1. If you can't get professionally fit then at least do some experiments with your seat height to see if it provides any improvement. I fixed a similar knee pain that you are describing by adjusting the height of my seat. You might find some tips here:
http://www.cptips.com/knee.htm