Steering Axis Inclination

Steering Axis Inclination (SAI) is the inward tilt (at the top) of the steering axis from vertical. The inclination angle is the angle between true vertical and a line passing through the center of the upper mount and lower ball joint as viewed from the front of the vehicle. SAI helps the vehicle track straight down the road and assists the wheel back intro the straight-ahead position. SAI on front-wheel-drive vehicles should be negative.