When cornering, an overturning moment is generated which makes the body roll outwards from the centre of turn. The immediate response is that the inner and outer swing arm rise and dip respectively at their pivoted ends so that the inner and outer wheels are compelled to tilt on their instantaneous tyre to ground centres, IWG1 and IWG2, in the opposite direction to the body roll.
For effective body roll to take place there must be two movements within the suspension geometry
1.The swing arm pivot instantaneous centres IWB1 and IWB2 rotate about their instantaneous centres IWG1 and IWG2 in proportion to the amount of body roll.
2 The swing arm pivot instantaneous centres IWB1 and IWB2 move on a circular path which has a centre derived by the intersecting projection lines drawn through the tyre to ground instantaneous centres IWG1 and IWG2.