Same as with a DF bike, if your knee hurts on top slide the seat back incrementally to get more distance; if it hurts underneath, slide it forward to shorten distance. As a shorter person I found the curvature of the seat didn't hit me right so I added a small seat cushion which angles me back slightly and up. There are lots of ways to tweak it to get comfortable but once you do I promise you will NOT miss a regular bike seat, lol.