Originally Posted by carleton

One thing to be mindful of when going to narrow bars is the reach. Even though the reach of the new narrow bars may be the same on paper as your current bars, the effective reach will be shorter because your hands will be closer together.

It's difficult to explain in words, but extend your arms in front of you as though you are riding 44cm bars. Note how far your knuckles are from you. Now move your hands closer together simulating more narrow bars. Your knuckles are now a couple of centimeters further away.

It's this reason why people wind up using stems longer than they expect to use to achieve the same upper body angles.