Very little to no friction through the front housing when I move the lever. I can feel slight friction in the rear housing because of the bends. I have a small frame bike (49cm) and I'm using the original rear housing that came with the bike. Front housing is relatively new since I changed my brifters (they run under the bar-tape). I'll check the caliper center bolt. Maybe it is too tight. When I was inspecting the caliper (when it was removed from the bike), after lubing it, I could tell that the movement wasn't completely smooth. In other words, I could feel that it's movement was not smooth through it's entire range. I could feel it had a slightly "jerky" movement when opening.