→In most suspensions, the roll centre is not a fixed point, but varies with suspension movement.
→Determining the roll centre is not easy, since the magnitude of suspension movement during cornering can be estimated only at low lateral accelerations, which is indicated with the example shown in the figure.
→The "bottoming-out" phenomenon has to be considered, which is the asymmetrical spring travel on the inside and outside wheels resulting from the asymmetrical spring forces which support the rolling moment of the body.
→Bottoming-out was feared in older vehicles with swing axles and high CGs, since rolling resulted in the height of the CG increasing → risk of roll-over.
→Bottoming out reduces considerably when the roll centre is positioned as low as possible and the quicker the roll center height drops during parallel compression of the body.