Echelon … or rotating pace line. A rotating pace line is not only a thing of beauty, it is a remarkably efficient way of getting a group of cyclists down the road faster and with less effort than they could as individuals. We all know that drafting is anywhere from a few percent to almost 70 percent easier than taking a pull depending on the circumstances. The amount of drafting advantage is determined by:
Wind direction and speed. A strong tail wind makes for less drafting advantage while a strong head wind gives a larger advantage to a drafter.
The degree of incline. Downhills offer much more drafting advantage to the point where a drafting rider may need to brake while the lead rider is pedaling hard. Climbs, especially steep ones can almost eliminate the advantage of drafting.
Speed. Similar to wind speed and incline, the faster the pace line’s speed, the bigger the drafting advantage.
This is a long piece. For the rest of it visit the Spectrum site here about mid way down the page. Look for the word echelon.