Anti-Dive and Anti-Squat

Definition

Anti-dive and anti-squat are expressed in terms of percentage and refer to the front diving under braking and the rear squatting under acceleration. They can be thought of as the counterparts for braking and acceleration in the same way that Roll Centre height relates to cornering. The main reason for the difference between front and rear values is the differing design goals between front and rear suspension, whereas suspension is usually symmetrical between the left and right sides of the vehicle.

Calculation

Anti-dive and anti-squat percentages are always calculated with respect to a vertical plane that intersects the vehicle’s Centre of Gravity.

Consider anti-dive as an example. First, locate the front instant centres of the suspension from the vehicle’s side view. Then draw a line from the tyre contact patch through the instant centre: this is the tyre force vector. Next, draw a line straight down from the vehicle’s centre of gravity. The anti-dive percentage is the ratio between the height at which the tyre force vector crosses the centre of gravity plane and the height of the centre of gravity itself, expressed as a percentage.

An anti-dive ratio of 50% means the force vector under braking crosses halfway between the ground and the centre of gravity.