Editing Automobile handling (section)

==== Yaw and pitch angular inertia (polar moment) ====
Unless the vehicle is very short, compared to its height or width, these are about equal. Angular inertia determines the [[rotational inertia]] of an object for a given rate of rotation. The [[Yaw angle|yaw]] angular inertia tends to keep the direction the car is pointing changing at a constant rate. This makes it slower to swerve or go into a tight curve, and it also makes it slower to turn straight again. The [[Pitch (flight)|pitch]] angular inertia detracts from the ability of the suspension to keep front and back tire loadings constant on uneven surfaces and therefore contributes to bump steer. Angular inertia is an integral over the ''square'' of the distance from the center of gravity, so it favors small cars even though the lever arms (wheelbase and track) also increase with scale. (Since cars have reasonable symmetrical shapes, the off-diagonal terms of the angular inertia [[tensor]] can usually be ignored.) Mass near the ends of a car can be avoided, without re-designing it to be shorter, by the use of light materials for bumpers and fenders or by deleting them entirely. If most of the weight is in the middle of the car then the vehicle will be easier to spin, and therefore will react quicker to a turn.