When a vehicle accelerates, weight is transferred to the rear, making the suspension “squat” from the extra weight. This chassis movement can be minimized or completely eliminated by using geometry to negate the squatting effect. On any rear suspension system (assuming it is a full forward system, even a 2 link) by moving the IC higher will have a higher percentage (the measurement given to anti squat) of anti squat making for a vehicle that doesn’t squat as much during acceleration and a lower IC will have a lower percentage and will squat more. Going overboard and running the bars high in the front in order to negate any squat will induce excessive roll over steer making the vehicle less stable while cornering. There is a fine balance that needs to be made when designing the “perfect” system. It is not so important to calculate out anti squat for a daily driver, but more important that you understand that it exists.
In this side view of the rear suspension, you cannot tell if there are 3 or 4 bars or how the bars are oriented. The instant center is found by extending the lines through the pivot points until they intersect. From there, anti squat is found by drawing a line from the IC to the center of the tire at the ground. Where that line crosses the center of gravity line it creates our measuring point ‘A’. The percentage of the line from the ground to our intersect point is the percentage of anti squat.