According to SAE, roll centre is the point in the transverse vertical plane through any pair of wheel centres at which lateral forces may be applied to the spring mass without producing suspension roll.



The concept of role centre becomes more clear when we consider it along with the centre of mass (centre of gravity), at which the centrifugal force acts during cornering. When the centre of mass is located at a point different from the role centre, a moment arm is created. Thus during cornering, a moment equal to the resultant force (which is the resultant of the centrifugal force and the weight of the sprung mass) multiplied by the moment arm, is experienced. As this moment, would be zero when moment arm is zero, the roll centre is also sometimes called moment centre. By how much amount the vehicle Rolls would depend upon the size of the moment arm, stiffness of the suspension springs and the anti roll bar.

However, when the vehicle rolls, the role centres shift. The vehicle dynamics is meant to control and limit this shifting of roll centres. Quick shifting of roll centres when the vehicle experiences small displacements can lead to stability problems. Raising the suspension roll centre or lowering the centre of gravity would decrease the vehicle roll. However, there are practical limitations in both of these. In fact, most well set up vehicles run a roll centre at slightly above or slightly below ground level.