Abstract: A butterfly valve for controlling gas flow is disclosed. The butterfly valve may include a valve body, the valve body defining a bore and a shaft configured for rotatable motion with respect to the valve body and including a shoulder. The butterfly valve may further include a disk housed within the bore, operatively coupled with the shaft, and configured to control gas flow through the bore based on a rotational position of the shaft relative to the valve body. The butterfly valve may further include a ball bearing operatively coupled with the shaft and including a ball and a race. The butterfly may further includes a spring configured to provide an axial force on the shaft, the axial force configured to press the shoulder of the shaft against the race of the ball bearing to prevent an outer edge of the disk from contacting an inner wall of the bore.