Exhibit A, the road cyclist going around a corner on a descent:
Exhibit B, the mountain biker going around a similarly flat corner:
In MTB, coaches teach “bike and body” separation especially in flat cornering drills. I believe the idea is to get the majority of your weight over the side of the tire where it makes the most contact with the ground, which is basically directly perpendicular on a flat, non-banked turn. A lot of times this is accomplished by leaning the bike towards the inside leg and rotating the hips into the turn.
This keeps your tires from slipping out, as opposed to being directly perpendicular over the axles, which would put all your force into the bottom of the tire which is at an angle in relation to the ground.
However, when watching road cyclists go around turns and hairpins, it seems like they are not leaving the saddle at all, nor are they leaning the bike towards their inside leg. The road does not look anywhere near banked enough to want to remain perpendicular over the axles, yet they still do. What is the difference in technique due to?
And lastly, how should corners be taken on gravel bikes and dirt road surfaces? Should they be treated as flat corners in MTBing?