Preload

To eliminate backlash and increase stiffness in a linear guide or ball screw, they can be provided with preload. This is usually accomplished by using larger rolling elements, which applies a force to the rolling elements inside the guide. The magnitude of the preload is defined as "negative clearance" in µm or, less commonly, as preload force in % of the load rating. As the amount of preload increases, the resistance to movement increases and the life of the component is reduced.