Pitch

Pitch Motion is when the vehicle’s chassis rotates around the Pitch Axis. The Pitch Axis is defined by the suspension geometry and can move as the suspension articulates. Positive Pitch is when the chassis dives while negative Pitch is when the chassis squats.
 

Pitch Center

The 2D kinematic Pitch Center is defined as the instantaneous center of rotation of the chassis about the ground, when viewed from the side of the vehicle. Similar to Roll Center, it is also dynamic and varies its position based on the movement of the suspension linkages.

The Pitch Center is formed by the intersection of the lines connecting the contact patch of the tire to the Instantaneous Center (IC) of the opposite end, as shown in the image above.

Pitch Axis

The Pitch Axis is the more appropriate method of determining the chassis pitch characteristics of a 3D suspension model. The Pitch Axis is the line that connects the left and right Pitch Centers. This is shown in the image below:

The pitch axis is defined by the red line in the analysis screen of OptimumK. If both front and rear suspension geometries are selected for analysis. OptimumK calculates both left and right pitch centers simultaneously when performing the chassis motion calculations.