Depends a bit on how far in front of the head tube; taping a 5mm diameter cable housing to a round tube with the axes parallel might actually be better than the round tube on its own. Dangling it diagonally across the tube axis several inches in front is going to be horrible, you get all the drag of the cable and make the flow over the tube worse too.
Depends a bit on how far in front of the head tube; taping a 5mm diameter cable housing to a round tube with the axes parallel might actually be better than the round tube on its own. Dangling it diagonally across the tube axis several inches in front is going to be horrible, you get all the drag of the cable and make the flow over the tube worse too.