The type of door that will work best for your shower depends on the design of your shower, the size of the opening and the practical space considerations that determine how your door should open. Showers generally fall into three types of designs.
Preload is the tension created in a fastener when it is tightened. This tensile force in the bolt creates a compressive force in the bolted joint known as clamp force. For practical purposes, the clamp force in an unloaded bolted joint is assumed to be equal and opposite of the preload.ither is acceptable, however a torque value defined for tightening the head does not necessarily apply to tightening the nut. Tightening the head vs. the nut can result in different nut factors and therefore change the torque required to achieve proper preload.
In this case, the preload length is 35mm and the resultant preload force is 17.5kg at zero travel. In other words, with this 0.5kg/mm spring and a setting at 35mm preload, you would have to put more than 17.5kg force on the end of the fork tube to create any movement at all.