i havent had any knee pain in a few years, really. i mean, if you are pedalling fluidly and making adjustments to your speed on the descent instead of shocking your knees into a locked skid, and when you climb if you arent really mashing and grinding, then your knees should be okay. the only times i'd have hurty knees was back when i'd ride in a more start/stop type of speed. or just from climbing poorly and inefficiently.