Steering Axis Inclination 42 The steering knuckle ball joints are closer together at the top than the bottom The steering axis(view from the front of the car places the centerline of the steering ball joints closer to the centerline of the wheel. this angle is known as steering axis inclination or sai 43 When the wheel centerline is to the outside of the center line of the steering axis where they intersect the road) the wheels tend to toe-out. This is caused by the road-tire resistance pushing back on the spindle causing it to swivel backward on the ball joints or toe-out. when the centerline of the wheel intersects the road at a point inside of the steering axis centerline intersection, the wheels tend to toe-in (tires are closer together in the front than in the back)Steering Axis Inclination 42 The steering knuckle ball joints are closer together at the top than the bottom. The steering axis (view from the front of the car) places the centerline of the steering ball joints closer to the centerline of the wheel. This angle is known as steering axis inclination, or SAI. 43 When the wheel centerline is to the outside of the center line of the steering axis (where they intersect the road), the wheels tend to toe-out. This is caused by the road-tire resistance pushing back on the spindle, causing it to swivel backward on the ball joints or toe-out. When the centerline of the wheel intersects the road at a point inside of the steering axis centerline intersection, the wheels tend to toe-in (tires are closer together in the front than in the back)