Editing Roller chain (section)

== Chain strength ==
The most common measure of roller chain's strength is [[tensile strength]]. Tensile strength represents how much load a chain can withstand under a one-time load before breaking. Just as important as tensile strength is a chain's fatigue strength. The critical factors in a chain's fatigue strength is the quality of steel used to manufacture the chain, the heat treatment of the chain components, the quality of the pitch hole fabrication of the linkplates, and the type of shot plus the intensity of shot peen coverage on the linkplates. Other factors can include the thickness of the linkplates and the design (contour) of the linkplates. The rule of thumb for roller chain operating on a continuous drive is for the chain load to not exceed a mere 1/6 or 1/9 of the chain's tensile strength, depending on the type of master links used (press-fit vs. slip-fit){{Citation needed|date=March 2010}}. Roller chains operating on a continuous drive beyond these thresholds can and typically do fail prematurely via linkplate fatigue failure.

The standard minimum ultimate strength of the ANSI 29.1 steel chain is 12,500 x (pitch, in inches)<sup>2</sup>.  
[[X-Ring chain|X-ring]] and [[O-ring chain|O-Ring]] chains greatly decrease wear by means of internal lubricants, increasing chain life.  The internal lubrication is inserted by means of a vacuum when riveting the chain together.