Drafting occurs when you ride behind another rider or group of riders. You gain the advantage of not having to work as hard (not put out as much power) because the other rider(s) help to break the wind and you can ride in their slipstream. Drafting percentage will vary greatly, depending on how close you are to other riders, what the wind direction is, and how many riders there are in the group.
While drafting, the Draft Wheel with a wind icon will pop up and the percentage of draft (blue area) will display graphically. The Drafting Wheel will show up on the upper part of the screen, to the right of the Stamina Wheel. As the draft increases, the blue area of the circle increases.
Tip: Practice your drafting skills. Get directly behind the pack, very close, and in the center for really good drafting benefit. This is the "sweet spot" for drafting and, if you can squeeze in front a few riders in the pack, too, that provides the best drafting.