How much faster when using drops
BikeCalculator attempts to quantify these different positions. I find it tends to overestimate speeds a bit (probably thinks all roads surfaces are smooth/good).
In my experience you gain about 0.5mph for each of these position shifts:
Flatbar -&gt; Tops of drop bar (narrower hands) -&gt; hoods -&gt; drops -&gt; aero hoods (flat forearms) -&gt; puppy paws (forearms on the tops)