Load distribution model
With metal guides, the close machining tolerances would cause narrow contact area and high surface pressure (fig. 1). That could cause damage or wear to the contact surfaces.
The higher degree of elastic deformation of polymer materials provides larger contact surfaces and a better utilization of the guide width (fig. 2). While the guide ring load is realistically not an even distribution, the guide ring load and width requirements are estimated with the projected area of the full dynamic surface (inside diameter for rod guides or outside diameter for piston guides) assuming the load is carried evenly across the surface (fig. 3).