A header for an agricultural vehicle includes: a header frame; a first deck plate carried by the header frame; a second deck plate carried by the header frame, the first deck plate and the second deck plate forming a gap therebetween defining a gap width and a width direction; a rotatable tube carried by the header frame and connected to at least one of the first deck plate and the second deck plate such that rotation of the rotatable tube adjusts the gap width; and a spring fixed to the rotatable tube and having at least one end captured by the second deck plate such that a force directed in the width direction acting on the second deck plate produces a spring force in the spring.