Body Roll Sensing
Published: December 8, 2016
Body roll sensing is a skill similar to traction sensing and speed sensing. To my knowledge "body roll sensing" as a label has not been in popular use, perhaps I get to coin it.
Body roll sensing is, then, feeling how hard the car is leaned laterally at a particular moment in time. Both relative and absolute body roll sensing is useful; let's start with the relative since it is conceptually easier.
Relative body roll is in relation to maximum attainable by the particular vehicle. It is primarily used when the driver is operating their own car on the track and can be a proxy, or an additional data point, for identifying how much of the available grip the car is using. The harder the car is turning, the more lateral acceleration it is generating and the more it is consequently leaning over. Advanced level drivers can tell how much of the grip the car is thus utilizing by feeling how much the car leans in a turn.
The reason body roll sensing is important is because I would associate traction sensing with how planted - or not - the car is at the moment. Given that R compound tires often have rather sudden breakaway, especially in rain, being able to feel body roll provides the driver with continuous input through a significant range of lateral accelerations while the tires are "planted" in all of them. This gives the driver ability to predict the point of traction loss with higher accuracy, and in particular should yield greatly increased confidence in rain driving.
Absolute body roll applies to the driver being in different cars, potentially unfamiliar ones, as well as on new tracks. For solo driving, absolute body roll sensing is a crucial skill to quickly ramp up the driver's pace on unfamiliar tracks, because it allows the driver to be progressive with their pace throughout the lap, hence maintaining a more consistent safety margin. The consistency of the safety margin promotes driver confidence which in turn enables the driver to increase their pace faster overall, even if each increase is smaller - because the driver does not exceed their expected aggression level.
For instructors, absolute body roll sensing permits ramping up the students' pace progressively in a very similar fashion while maintaining the desired safety margin. It also leads to early corrections of excessive aggression on the student's part, again fitting the student into a tighter envelope of pace vs accepted safety margins. The result is generally faster introduction of advanced driving techniques as well as aggression to the student's driving.