This one's a two-part question. I've noticed several distinct styles of riding those paved descents where speed limits and other safety considerations allow for high speeds. Some of them make perfect sense, while others...don't. Some cyclists coast the descent using the same general posture they do on the flats. Others, usually but not always roadies, also coast but while clearly trying for one of a couple of 'aero' postures: arms either out in front on aero bars or down in the drops, elbows tucked close to the body, back perfectly flat and parallel with the road, knees tucked close to the frame, etc. It varies from cyclist to cyclist, but with obvious similarities. Some cyclists seem to spin through the descent, but without putting much if any power into doing so. I do that a lot in places where speed limits, visibility, or other concerns prohibit higher speed. A few cyclists really attack the descent, seeking the highest speed possible within safety constraints. Sometimes, their posture mimics the 'aero coasters', only they spin for all they're worth. Other times, their posture is similar to how they'd look on the flats. A few scary ones get too deeply into the descent and forget that it's critical to hold a stable, predictable line at all times when you're bicycling on public roads with automobiles. How do you roll descents? Why? I totally get that not everyone feels the need or has the comfort level to really attack a descent. No judgment, no problem. Everyone rides differently, and with different perceptions of what is and is not safe for them. Normal posture coasting or low/no-powered spinning makes perfect sense here. Similarly, I get the desire to attack the descent for all you're worth. Where it's safe to do so, that can be a heck of a lot of fun. Perhaps going aero while attacking makes for higher speeds. It at least stands to reason. That brings us at last to the 'aero coasters', who I simply don't understand. They appear to be striving for the best possible speed in terms of aerodynamics, but without pedaling, they top out far below what's possible with even moderate effort and a normal posture. That's not a judgment or condemnation, simply an expression of observed reality. Powering through a descent will get you down much faster than will coasting it, regardless of posture. I understand not seeking the highest possible safe speed, but confusion sets in when I see people in a posture which screams 'fast' but isn't unless one is also spinning. Makes me wonder what I may be missing. I can think of some pejoratively dismissive answers, but if I presume reasonable people doing reasonable things, I tend to come up empty on this one. Any ideas?