Lightweenie wrote:There were some posts about a narrower or wider bar changing the reach. If you do the (basic geometry) calculations you'll see that the reach difference for a normally proportioned bike when making the bars 2cm wider or narrower is negligible. You can safely ignore this when deciding on the width of your bars, and keep your stem.
It isn't really about the simple geometry. When narrowing bars, one is also changing the concept of your positioning. Just like putting on aero bars moves you farther forward at the position where you grip your bars, so do narrower road bars. If you don't, you are bringing your elbows in closer to your chest and you actually risk impingement with your rib cage. Narrower bars can have an additional benefit when a bit more stem extension is involved, and one can also consider a slightly different saddle angle consistent with a different amount of hip rotation in that more extended position. It's not just basic geometry of the arms in isolation.