Roll Center
Roll center is a suspension-analysis reference used to describe how lateral forces and body roll are related at an axle.
More than one definition
A kinematic roll center is derived from suspension geometry and instantaneous wheel motion. A force-based roll center is derived from how lateral tire forces are transmitted to the body. In transient analysis, a dynamic roll axis may also be used. These definitions can produce different locations and should not be mixed without explanation.
Roll-center height affects geometric force paths and the relationship between lateral force, body roll moment, jacking, and spring or anti-roll-bar deflection. It does not remove lateral load transfer, which is governed by vehicle acceleration, mass, track, and center-of-mass height.
The kinematic location can move with heave, roll, steering, and suspension travel. A single static height is therefore only one operating point, and the front and rear centers together do not fully predict handling.
For the wider connection between geometry, forces, and body motion, see Suspension Kinematics and Vehicle Dynamics.