Sit in a chair with your heels under your knees. Notice how easy it is to keep your knees together. This is the seating position on the T120. Now move your feet back, closer to your butt. Your knees will spread. When your feet are in this position on a bike, you have to make an effort to keep your knees together at high speed. This effort is uncomfortable when it has to be done all day long. My knees splay for this reason on my T100, but they don't on my T120.