What does the term "roll center" refer to in suspension design?

The term "roll center" in suspension design refers specifically to the point around which the vehicle rolls during cornering. When a vehicle navigates a turn, the forces acting on the suspension create a lateral movement. The roll center is a theoretical point in the vertical plane of the suspension geometry, which affects how the vehicle behaves during this lateral movement.

Understanding the location of the roll center is crucial for vehicle dynamics because it directly influences body roll, weight transfer, and overall handling characteristics. A higher roll center will generally reduce body roll in corners, promoting more stability, while a lower roll center can allow for more body roll, potentially improving traction but sacrificing some stability.

In contrast, the other provided options describe different concepts that are not synonymous with roll center. The rotational axis pertains to the general motion of the vehicle rather than the specific mechanics of suspension. The average height of suspension components is a different measurement that does not directly correlate with how the vehicle behaves during cornering. Lastly, the central pivot point of the steering system is related to steering geometry and vehicle direction, not specifically to body roll dynamics.